Suregork Loves Beer

Beer Reviews, Homebrew, Rambling

May 17, 2016
by suregork

Effects of ploidy on new lager yeast hybrids

As I’ve mentioned previously in many past posts (e.g. here, here and here), I’m working with and researching the properties of newly created lager yeast hybrids (for my PhD project). In the linked posts, you can read about some of our initial results from the project. These mainly established the technique and showed that de novo lager hybrids can exhibit hybrid vigor over their parent strains. Since then I’ve been looking more closely at how hybrids made from the same parent strains, but with varying ploidy levels (i.e. chromosome numbers), behave in regards to fermentation performance, aroma compound production and stress tolerance. We had some very interesting results, and we saw (at least with our hybrids) that the hybrids with higher ploidy level performed better and produced more aroma-rich beer. In order to try to understand why, we sequenced the hybrids and performed transcriptional analysis on selected genes. We saw that the higher ploidy hybrids had higher copy numbers of several genes related to aroma synthesis, and these were also transcribed at higher levels during fermentation. I held a presentation about this research at the 5th International Young Scientists Symposium on Malting, Brewing and Distilling in Chico about a month ago. You can download the presentation slides below! I’m also very happy to announce that we recently had a manuscript on this work accepted for publication in Applied Microbiology and Biotechnology. ‘Ploidy influences the functional attributes of de novo lager yeast hybrids‘ was just published online, and you can find a link to the publication below as well (it is Open Access!).


Link to the publication:

Link to the presentation slides:


The genomes of hybrid organisms, such as lager yeast (Saccharomyces cerevisiae × Saccharomyces eubayanus), contain orthologous genes, the functionality and effect of which may differ depending on their origin and copy number. How the parental subgenomes in lager yeast contribute to important phenotypic traits such as fermentation performance, aroma production, and stress tolerance remains poorly understood. Here, three de novo lager yeast hybrids with different ploidy levels (allodiploid, allotriploid, and allotetraploid) were generated through hybridization techniques without genetic modification. The hybrids were characterized in fermentations of both high gravity wort (15 °P) and very high gravity wort (25 °P), which were monitored for aroma compound and sugar concentrations. The hybrid strains with higher DNA content performed better during fermentation and produced higher concentrations of flavor-active esters in both worts. The hybrid strains also outperformed both the parent strains. Genome sequencing revealed that several genes related to the formation of flavor-active esters (ATF1, ATF2¸ EHT1, EEB1, and BAT1) were present in higher copy numbers in the higher ploidy hybrid strains. A direct relationship between gene copy number and transcript level was also observed. The measured ester concentrations and transcript levels also suggest that the functionality of the S. cerevisiae– and S. eubayanus-derived gene products differs. The results contribute to our understanding of the complex molecular mechanisms that determine phenotypes in lager yeast hybrids and are expected to facilitate targeted strain development through interspecific hybridization.

May 13, 2016
by suregork

Report from the 5th Young Scientists Symposium in Chico (Part 2)

It took a little longer than expected to finish the second part of my summaries of the presentations at the 5th International Young Scientists Symposium on Malting, Brewing and Distilling, but here they are. You can find the first part here. I will hopefully have time to post the final part next week. I will also be posting a summary of my own presentation on new lager yeast hybrids.

  • Screening for the brewing ability of non-Saccharomyces yeasts by Maximilian Michel

Maximilian talked about the use of non-conventional yeasts for beer production and he had screened a range of non-Saccharomyces yeasts for brewing potential. Yeast isolates were first identified with genetic fingerprinting and RT-qPCR, and then sent through an initial screening test, which included growth on various carbon sources (glucose, fructose, sucrose, maltose, maltotriose and melibiose), hop resistance (various concentrations of iso-alpha acids), ethanol tolerance (various concentrations of ethanol) and phenolic off-flavour production. Promising strains were then chosen for 2L fermentations. He had focused especially on Torulaspora delbrueckii (but he had also looked at Schizosaccharomyces pombe, Pichia anomala, Hanseniaspora uvarum, Kluyveromyces lactis and Kluyveromyces marxianus), and out of the ten strains he had fermented with at ‘larger’ scale, only one was able to use maltose (and maltotriose). That strain also produced a fruity and berry-like flavour profile. So there are definitely gems to be found in the vast range of wild yeast that are available in nature.

  • Lachancea thermotolerans in primary beer fermentations by Jen House

Jen continued on the topic of using wild yeast in beer fermentations. Her research was on the use of Lachancea thermotolerans, which is an interesting species because of its ability to produce lactic acid. Hence, there is potential to use it in pure culture fermentations for the production of sour beer. Jen had tested three different strains of various origins in wort fermentations, and found that all three were able to use maltose, but not maltotriose. The three strains also produced more lactic acid and glycerol than the S. cerevisiae control. They also seemed to have quite low O2 requirements and were resistant to iso-alpha acids up to at least 60 IBU, which makes them interesting for brewing use. The pH only dropped to around 4.2 in her experimental fermentations, which means that they will only produce a mildly tart beer and may not be suitable for sour beers (as the only microbe). Lachancea yeasts have been isolated from the bark of oak trees, so that may be a good place to start looking in case you are interested in trying to isolate your own!

  • Biodiversity of yeast and lab population isolated from Beninese African Sorghum Beer Starter by Sedjro Emile Tokpohozin

Emile has been looking at the biodiversity of Beninese sorghum beers by isolating yeasts and lactic acid bacteria from starter cultures brought from Benin. These starter cultures aren’t made from pure yeast cultures, rather a small amount of beer from the previous batch is used as a starter culture for the next. Emile had isolated (identification by ITS-PCR and MALDI-TOF-MS) a range of yeasts (e.g. Saccharomyces cerevisiae, Candida krusei, Candida ethanolica and Debaryomyces hansenii) and lactic acid bacteria (Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus helveticus, Lactobacillus brevis and Lactobacillus paracasei) from a starter culture, and he further screened these for the ability to use various carbon and nitrogen sources, as well as beta-glucosidase ability (in order to break down the cyanogenic compound dhurrin that is found in sorghum). Several possible candidate isolates were identified and these are to be used in some pilot-scale fermentations next. Again shows how much ‘wild’ microbes are out there that are potentially useful in brewing!

  • Invited Speaker: Yeast culture collections by Kyria Boundy-Mills

This talk was a bit different, as Kyria talked about the Phaff yeast culture collection (of which she is the curator of). The Phaff collection is the fourth largest in the world, and contains thousands of yeasts. Many of the deposited yeasts have not been characterized very well, so Kyria talked about the possibility of finding ‘hidden gems’ in the collection. These could have some very interesting properties and phenotypes, relevant not only to the brewing industry, but also e.g. the biofuel industry (oleaginous yeast).

  • Relationships between the speed of fermentation and levels of flavor compounds post-fermentation by Maria Josey

Maria had examined the beer aroma compounds and modelled the fermentation kinetics (using a logistic model) of 10 successive fermentations using serially repitched yeast. The 10 fermentations all behaved quite similarly, with only minor differences in fermentation rate. There also didn’t seem to be any relationship between fermentation rate and number of times the yeast was repitched. This shows that you can easily reuse your yeast for over 10 generations without any significant effects on your fermentation (as long as your hygiene practices are good). Positive linear correlations were found though between the concentrations of several aroma compounds and the maximum fermentation rate (the B parameter in the model). Faster fermentation leads to more isoamyl acetate, isobutyl acetate, ethyl hexanoate and ethyl octanoate, which of course is something that seems logical as these compounds are synthesized from metabolic intermediates.

  • Omics analysis revealed multiple stress responses of lager yeast in the process of autolysis by Jinjing Wang

Jinjing had studied the yeast responses associated with autolysis by performing proteomic and transcriptomic analysis on yeast strains with different tendencies to autolyse. She also presented various methods for the quantification of autolysis, including measuring total protein in beer, the stability of the redox potential and nucleic acid release. Using microarray analysis they had identified a range of genes that were down- and upregulated in yeast strains that showed high tendency for autolysis (e.g. RLM1 and UBC4). To confirm the roles of RLM1 and UBC4 in the autolysis process, these genes were both knocked out and overexpressed in a production strain. Overexpression of RLM1 and knocking out UBC4 led to increased autolysis. However, one must keep in mind that autolysis is a complex process that is influenced by a range of cell functions and genes.

  • Energy state model for bottling plants by Isabel Osterroth

Isabel held the only presentation in the ‘Packaging’ topic, and she talked about an energy state model which she had developed for bottling plants. Sustainability and reducing energy use, combined with the fact that bottling plant models haven’t been made before, was the driving force for creating the model. The model described the energy use of various machines in the bottling plant depending on their operational state (machines use energy even when idle). A model that was able to predict the energy use of all the separate functions in the bottling plant was successfully created, and future work will include the use of the model for optimization purposes.

  • Impact of ascorbic acid additions in mashes by Joe Williams

Joe talked about his research on supplementing ascorbic acid to the mash, and gave a virtual tour of the pilot brewery at UC Davis. The motivation for adding ascorbic acid to the mash was to increase thiol and polyphenol formation and to decrease color development in the wort. The study was very preliminary at the moment, and it will be interesting to see the final results. The pilot brewery at UC Davis was quite impressive, featuring a six-vessel 170L brewhouse and four 20L nano-breweries. I am quite jealous.

  • Optimizing hop aroma in beer dry hopped with cascade utilizing glycosidic enzymes by Kaylyn Kirkpatrick

Kaylyn talked about the use of various glycosidic enzymes in dry hopped beer in order to release glycosidically bound aroma compounds. She had tested a range of commercial Rapidase enzymes and what effect they had on the concentrations of various hop aroma compounds in a beer dry hopped with Cascade. The addition of these enzymes seems to have had quite little effect on linalool concentrations, but the concentration of geranyl acetate seems to have been enhanced with the ‘Rapidase Hoptimase’ enzyme. Their sensory panel also noticed an increase in ‘tropical fruit’-like aroma, which could be attributed to several compounds that weren’t quantified in this experiment. It seems like an interesting idea though; using e.g. Cascade in combination with a glycosidic enzyme to replicate the aroma profile of some of the modern aroma hops (e.g. Citra). Not sure how economical such a solution is though?

  • Investigating sources of variation during dry-hopping by Daniel Vollmer

Daniel talked about methods to reduce the amount of variability between replicates in dry hopping experiments. Daniel had noticed in earlier experiments that there was quite large variation between his replicates during dry hopping experiments at pilot-scale, and thus attempted to locate sources for this variation. One of the key findings was that oxygen pickup has a large (negative) effect on hop aroma intensity, and this seemed to have been one of the largest sources of variation. Other sources was the raw material (i.e. the hops cones), which for future experiments will be ground. Another interesting observation, which I mentioned already in the summary of Tom Shellhammer’s keynote lecture, was that there is huge variability in oil content within the same hop cultivar (e.g. Cascade) from different farms. Also very interesting, as I mentioned, was that there seemed to have been no correlation between oil content and aroma intensity. So there are clearly other factors that affect hop aroma intensity as well.

April 29, 2016
by suregork

Report from the 5th Young Scientists Symposium in Chico (Part 1)

I apologize again for the inactivity on the blog. I haven’t been brewing much the last half a year. The wife and I bought a house in the end of last year and we’ve been renovating it since. We finally moved in a couple of weeks ago, and have started settling in. So soon I’ll be able to return to brewing again! Anyways, last week I attended the 5th International Young Scientists Symposium on Malting, Brewing and Distilling, which was arranged at Sierra Nevada’s brewery from April 21-23, 2016 in Chico, California, USA. First of all I want to thank Ken Grossman, Sierra Nevada, Charlie Bamforth and all the other organizers for a fantastic conference (especially Sierra Nevada for their generosity)! The conference featured great scientific and social program, awesome food, a relaxed atmosphere, amazing people and delicious beer! I myself presented some of the recent research we’ve been conducting on lager yeast hybrids at VTT the past year (I’ll post a link to the presentation slides soon!). To sum up, we’ve been looking at how the ploidy of new lager yeasts affect their phenotypical properties. I’ll be writing up a more detailed post on this particular research soon, as we just had a manuscript on this work accepted.


As I mentioned, there were a lot of interesting presentations during the conference! I thought I’d write some short notes / summaries of all the presentations in case you are interested. Since there were a lot of presentations, I’m splitting this post into three parts. Anyways, here is the first third of the summaries:

  • Keynote: How Craft Brewing is Transforming the Way We Think About Hops and Hop Flavor by Tom Shellhammer

Tom opened the conference with an interesting talk on the current situation of hop use in the craft industry and hop research at OSU. Craft brewers are using more and more of the global hop production, which also has shifted from being ‘bitter hop’-dominated to being ‘aroma hop’-dominated. Tom also reminded the audience that 1 IBU is not the same as 1 ppm iso-alpha acid. This is particularly relevant with heavily dry hopped beers, where oxidized alpha acids (which are bitter, but not as bitter as iso-alpha acids) can influence the IBU value. In some commercial (dry hopped) beers that had been analysed at OSU, they had observed very high levels of oxidized alpha acids. Another point that was brought up, was that the perceived bitterness gets saturated at high IBU levels (i.e. very little sensorial difference between a 80 IBU beer and a 100 IBU beer). Tom also showed a very interesting figure (which Daniel Vollmer showed again later in his presentation), showing the relationship between hop oil content in Cascade hops sourced from different farms and the hop aroma intensity in beers brewed with these hops (determined by a sensory panel). What was extremely interesting was that there seemed to be no correlation what so ever. The beer brewed with the Cascade hops with lowest oil content actually seemed to have one of the highest aroma intensities. Furthermore, many of the Cascade hops that had the highest oil contents produced beers with the lowest aroma intensities. This just shows that blindly looking at hop oil contents in hops doesn’t actually tell very much about what kind of hop aroma it will give to the beer. If I remember correctly, Tom also suggested that there was no correlation between linalool or myrcene concentrations and the hop aroma intensity either, meaning that there are other key aroma compounds responsible for hop aroma out there that still need to be identified.

  • Towards the release of a 2-row barley variety for California craft malting and brewing by Joshua Hegarty

Joshua talked about how they have attempted to breed a 2-row barley variety that would be suitable for the ‘harsh’ growing conditions in California. These include an abundance of plant pathogens and dry conditions. They had crossed different parent strains, and selected superior varieties which they had then tested in the field. The new breeding lines had shown good yields and malting quality in the field trials. Using gene mapping they had also found several regions associated with disease tolerance in barley.

  • Impact of barley varieties on malt and beer flavor by Lindsay Barr

Lindsay presented some research on the influence of barley varieties on malt and beer flavour that had been carried out at the New Belgium Brewing. Barley variety seems to have quite a big influence on both wort and beer flavour (at least according to their sensory panel). However, there didn’t seem to be any correlation between the flavours that were observed in the wort and the beer. Beer age seemed to have had a bigger impact on the beer flavour than the barley variety.

  • Selective pressurized liquid extraction of hop oil from hop cones by Katy Orr

Katy talked about some of the hop-related research that had been done at Sierra Nevada Brewing. Her background was in environmental chemistry, where she had used different extraction methods to quantify hydrocarbons from environmental samples. Here, she talked about how they had tested two different extraction methods, selective pressurized liquid extraction and Likens Nickerson distillation, to test the efficiency of their hop torpedo. Both methods seemed to have yielded quite similar results for some of the compounds that were analysed. However, the main points that were brought up were that the extracted amount does not equal the actual contents and subsequently the importance of good internal standards (that behave chemically and physically as similarly as the compound of interest as possible).

  • Pro-oxidative effects on the storage stability of German Perle and Czech Saaz pellet hops by Mark Zunkel

Mark had compared the stability of Perle and Saaz hops exposed to oxygen at room temperature during a 9 month period. The hop storage index (HSI; which measures the loss of alpha and beta acids spectrophotometrically) of Perle remained quite stable for around 4 months, after which there was a more rapid loss of the hop acids. Saaz seemed to have remained slightly more stable than Perle, but also experienced a more rapid loss in the latter half of the experiment. Unsurprisingly, both hop varieties suffered a rapid loss of hop oil in the pro-oxidative environment (50% loss of hop oil in a week). This just shows that aroma hops should be stored cold and without the presence of oxygen!

  • The effect of hopping regime, cultivar and yeast ß-glucosidase activity on terpene alcohol levels in beer by Daniel Sharp

Daniel talked about the research he had been doing on the release of hop terpenes into beer from hop glycosides. This is an interesting topic for brewers interested in hop aroma, as aroma-active compounds can potentially be released during fermentation through the hydrolysis of hop-derived glycosides in the beer. He had tested the beta-glucosidase activity of a wide range of brewing yeast strains, and then selected strains with high and low activity. Surprisingly, beta-glucosidase activity didn’t seemed to affect the maximum hydrolysis level that was achieved during fermentation (and this level was much lower than the positive control where purified enzyme was added to wort). It just took a slightly longer time to reach this level with the low activity strain. Daniel didn’t seem to see any correlation between beta-glucosidase activity and the amount of aglycones in the beer. Higher glycoside extraction was achieved with whirlpool and dry hopping compared to kettle hopping. Some varieties that seemed to be high in glycosides were Columbus, Centennial, Simcoe and Summit.

  • Creating a gin utilizing novel Scottish Botanicals: A University-Industry collaboration by Margaux Huismann

Margaux talked about her MSc project, which was carried out as a collaboration between Edinburgh Gin and ICBD. During the project, she and 3 other students had developed a gin featuring Scottish (coastal) botanicals. They went to the Scottish coast to forage for interesting botanicals, and then distilled them in lab scale to develop a recipe. The recipe was then used at larger scale at the distillery to produce a commercial product. One botanical in particular, Bladderwrack, seemed to have given off a strong ‘fishy’ aroma during distillation, and its volatile aroma compounds were analysed in more detail. We later got to try the actual gin, and it was really nice (not at all as salty or ‘fishy’ as I first was expecting). Thanks Margaux!

  • Keynote: Impact of brewing practice on yeast performance by Katherine Smart

Katherine talked about some of the research she has been doing the last 15 years. This research has been focused mainly on repitching, yeast viability, stress tolerance and petite mutants. Most interesting to me was the work on why ‘1st Generation’ yeast (i.e. yeast that have already undergone one fermentation) seem to start fermentation faster than ‘0 Generation’ yeast (i.e. yeast that come straight out of the propagator). One cause, is that G1 yeast bud faster than G0 yeast (i.e. enter the replication cycle faster) and (if I remember correctly) are able to use glucose faster from the wort. G1 yeast also seem to use less FAN from the wort, which I found interesting (less nitrogen demand or more biosynthesis?). They had also used high-throughput screening systems to isolate osmo- and ethanol tolerant strains. A quite interesting remark was that strains are seldom good at both, i.e. an osmotolerant strain is rarely ethanol tolerant as well. One good point that was made regarding these high-throughput systems is that you find what you are looking for. These isolates may have high tolerance, but may otherwise perform badly in wort or produce off-flavours.

  • Cambridge Prize Lecture: The Influence of Yeast Handling on Petite Mutant Formation by Stephen Lawrence

Congratulations to Stephen for winning the Cambridge Prize! Stephen talked about the research he had carried out, which won him the Cambridge Prize. His research was focused on petite (or respiratory-deficient) mutants in brewing, and during his presentation he also talked about various stresses the yeast are subjected to during fermentation. Petite mutants (i.e. cells with damaged mitochondrial DNA) form during fermentation as a result of fermentation stresses, and these can accumulate when yeast is repitched for several generations. These petites perform worse in several regards compared to wild type cells, so their accumulation is not desirable from a brewer’s point of view. Some interesting points that were brought up, were that older cells (i.e. cells with more budding scars) were more susceptible to petite formation and that lower mtDNA copy numbers actually didn’t increase the likelihood of petite formation (e.g. older cells tend to have more mtDNA copy numbers). This seems to suggest that the accumulation of mtDNA damage has a higher impact on petite formation than the copy numbers of mtDNA. This was a very interesting talk, and the topic still seems to be quite poorly understood. It will be interesting to follow the topic in the future.


Parts two and three will be posted during next week!

January 29, 2016
by suregork

Tasting Impressions: J&L Wedding Dunkel and Pale Ale

As I mentioned in my previous blog post, I brewed two batches of beer to my friends’ wedding that took place two weeks ago. Today I thought I’d finally write some tasting notes in case someone is interested in trying the recipes. I’m slightly more happy with the Pale Ale, but I have brewed the recipe (or at least variations of it) several times. Both beers were good though! Let’s start with the Dunkel!


The beer pours with a light brown color and it is slightly hazy. The color was a bit lighter than I expected, but then again I didn’t use that much roasted malts in this. A cream colored head is formed, but it collapses quite quickly leaving drapes of lacing along the glass. The appearance is okay. I’m not really sure why it hasn’t cleared despite the 2 months it was lagering in the keg at 0C. The aroma features some light roastiness (hints of dark chocolate), dark fruits, dark malt bread, and syrup/molasses. The aroma is quite clean and promises a malt-forward flavor. The taste is similar to aroma, with a light roastiness and bready malt tones dominating. Towards the end, a slight yeasty fruitiness joins in together with some grassy hops. The finish is quite dry and lightly bitter. Unfortunately the flavour is slightly boozy/solventy as well, which hints that the fermentation was not perfect. It was fermented in a temperature controlled fridge, so perhaps I underpitched or underaerated. The body is on the light side and the carbonation level is a bit too high. It is easy to drink and quite refreshing though. All in all, I’m quite happy, but you can definitely tell that the fermentation didn’t go perfectly. I’ll have to try again next winter.


The Pale Ale was more to my taste, and it was also the beer that got most compliments at the wedding (it also ran out first). It pours with a quite clear golden-amber color (similar to Sierra Nevada’s Pale Ale). This was slightly hazier at the wedding, so it cleared up nicely during two weeks in the fridge. A fluffy white head is also formed during the pour, and it collapses slowly leaving lots of lacing along the glass. A really nice appearance! There is lots of citrus (especially grapefruit), resin and grassy herbs in the aroma. As you can guess, it is very hop forward. The aroma is otherwise very clean and promises a really tasty beer. The taste begins with a slightly sweet caramel cookie flavor, and it is quickly joined by grapefruit and ‘tropical fruit’ hop flavors. Very fruity. The finish ends in a moderate bitterness, that has a slightly grassy and herbal quality to it. Maybe from the dry hops? I remember the beer being grassier at the wedding, so maybe it has cleaned up during these two weeks. The flavor is also very clean, and you can tell the fermentation went well. The beer has a medium body and carbonation level, and is very easy to drink and really refreshing. A really nice APA that suits my taste buds perfectly. It went quickly during the wedding so it seemed like I wasn’t the only one who liked it!

The labels to the beers were designed by my lovely wife ♥

January 23, 2016
by suregork

Homebrew: Wedding APA

Last weekend I attended my friends’ wedding (thanks for the great party!), to which I had brewed two batches of beer. The first was a Dunkel and the second an American Pale Ale. I brewed the APA back in November with my brew mate, but I seemed to have forgotten to post the recipe and brewday notes. As I wrote in the Dunkel post, I’ve noticed that the most popular beers during these kinds of events are balanced and easy-to-drink beers. American Pale Ales with a relatively mild bitterness seem to be especially popular, so I used the recipe of my own Wedding APA as a base for this beer.

The malt bill was kept simple, with Maris Otter, Munich and Carapils. For the hops, I used up some opened bags of American hops from the freezer. The bitterness ended up a bit on the high side, but it was still suitable for the style. For the yeast I chose my ‘house yeast’ WLP002, which flocculates well and leaves a nice flavor profile. The brewday went quite smoothly and the beer was really popular during the wedding! I will be posting tasting notes of both the beers in an upcoming post!

Recipe Details

Batch Size Boil Time IBU SRM Est. OG Est. FG ABV
40 L 60 min 53.4 IBUs 12.3 EBC 1.055 SG 1.013 SG 5.6 %

Style Details

Name Cat. OG Range FG Range IBU SRM Carb ABV
American Pale Ale 10 A 1.045 - 1.06 1.01 - 1.015 30 - 45 9.9 - 27.6 2.3 - 2.8 4.5 - 6.2 %


Name Amount %
Pale Malt, Maris Otter (Thomas Fawcett) 7 kg 73.68
Munich 2 kg 21.05
Cara-Pils/Dextrine 0.5 kg 5.26


Name Amount Time Use Form Alpha %
Simcoe 20 g 60 min Boil Pellet 11.4
Centennial 10 g 60 min Boil Pellet 8.8
Amarillo 20 g 30 min Boil Pellet 8.9
Simcoe 20 g 30 min Boil Pellet 11.4
Amarillo 40 g 30 min Aroma Pellet 8.9
Simcoe 30 g 30 min Aroma Pellet 11.4
Cascade 20 g 30 min Aroma Pellet 5.5
Amarillo 40 g 5 days Dry Hop Pellet 9.2
Cascade 40 g 5 days Dry Hop Pellet 5.5
Simcoe 30 g 5 days Dry Hop Pellet 13


Name Amount Time Use Type
Gypsum (Calcium Sulfate) 13.00 g 60 min Mash Water Agent
Calcium Chloride 12.00 g 60 min Mash Water Agent
Lactic Acid 4.00 ml 60 min Mash Water Agent


Name Lab Attenuation Temperature
English Ale (WLP002) White Labs 75% 18.33°C - 20°C


15 Liter top up!

November 4, 2015
by suregork

Creating a new ’super fruity’ yeast strain – The best of Conan and WLP644?

In this blog post I’m briefly going to summarize how I created and improved a hybrid yeast strain between Conan (isolated from a can of Heady Topper in 2013) and WLP644. I’ve used both strains in several homebrews previously, and I’ve really liked the fruity esters they produce during fermentation. While Conan produces a really nice aroma profile, it doesn’t seem to attenuate as well as say WLP001 (most probably as a result of incomplete maltotriose use). This means that it often leaves a slight sweetness in the beer, and is a bit unpredictable. With WLP644 I’m not that sure. I’m fairly sure it uses maltotriose and ferments the beer quite dry, but this observation is only based on a single homebrew I’ve done with it. It seems to grow and ferment slightly slower than most ale strains though. So, I had the idea to generate a hybrid between the strains, in order to create the ultimate ‘super fruity’ yeast strain:

  • Lots and lots of fruity esters
  • Complete maltotriose use for high attenuation
  • Bonuses are fast fermentation and moderate flocculation

Spore-to-spore mating is the traditional method of generating yeast hybrids, but I myself am more of a fan of rare mating. Also, spore-to-spore mating couldn’t really be applied here in this case because of the poor sporulation ability of Conan. To begin, I needed to ‘tag’ the parent strains with selection markers. To do this, I selected spontaneous auxotrophs of Conan (ura-) and WLP644 (lys-) on 5-FOA and α-AA agar, respectively. This means that my Conan mutant strain isn’t able to synthesize its own uracil anymore, while the WLP644 mutant strain isn’t able to synthesize its own lysine anymore. Any hybrid between these two would inherit the functional genes from the other parent, meaning the hybrid is prototrophic again, and can again synthesize its own uracil and lysine. Hybrids can thus be selected on minimal media, which doesn’t contain uracil and lysine.


The actual hybridization process is easy, all I have to do is mix cultures of both parent strains in rich media (YP-Maltose in my case), incubate for 3 days, pellet, wash and starve the yeast, and finally spread it out on minimal media agar. Any colonies appearing on the minimal media agar are most likely hybrids. The other option is that the colonies are the parent strains, which have undergone spontaneous mutations to return to being prototrophic again. In order to ensure that we in fact have hybrids, the colonies are first purified by restreaking on fresh minimal media agar, and then transferring and streaking a single colony to YPM agar. DNA is then extracted from a single colony on the YPM plate, and interdelta-PCR is performed on the DNA.

Interdelta-PCR is a technique that is usable for differentiating Saccharomyces cerevisiae strains. Below you can see the gel and the profiles that our hybrids (H1-H4) and the parent strains produce. As we can see, the hybrids contain DNA (i.e. the bands) from both parent strains, so it is confirmed that we have successfully generated a hybrid. This is especially evident in the areas I’ve marked with red asterisks on the DNA Ladder. I won’t go into more details on the mating mechanisms, but the short answer is loss of heterozygosity at the MAT locus (for more details see here). Being a result of rare-mating, this hybrid will most likely be tetraploid (assuming that both parent strains are diploid), and contain approximately the whole genome of both parent strains (as can be seen from the gel below, hybrid H2 has already lost some DNA).


To stabilize the hybrids and also generate some potentially interesting phenotypes, I utilized meiotic recombination and segregation! During ascospore formation in yeast, meiosis and chromosomal crossover takes place, during which genes are shuffled between pairs of chromosomes. First we have to sporulate our hybrid (this can be done on 1% potassium acetate), then treat the forming ascospores with a lytic enzyme (e.g. Zymolyase), and finally dissect the ascospores with a micromanipulator. I choose to do this to hybrids H1 and H2. Both strains sporulated quite poorly and the spores had low viabilities as well (34% for H1 and 8% for H2). I selected the fastest growing colonies for further characterization, and this was four segregants from hybrid H1: H1/A4, H1/C3, H1/C4, H1/H1. The characterization was done in some small-scale (35 ml) wort fermentations. This was done in order to confirm that they still are able to grow and ferment well in wort and that they produce a lot of fruity esters.


tetrad_dissectionThe four segregants that were chosen for further characterization

The small-scale fermentations were carried out in 15 °P wort (specific gravity: 1.060), because I thought this would be representative of a typical IPA wort. 35 ml of wort was added to pre-weighed and airlock-capped plastic tubes (50 ml), after which 10 million cells / ml of wort of each yeast strain was added to start the fermentations. Fermentations were carried out at 18 °C (in retrospect, this might have been a little low), and they were monitored daily through mass loss. The alcohol content of the final beer was measured with an Anton Paar DMA5000M + Alcolyzer. Our HS-GC is in heavy use at the moment in other projects, so I wasn’t able to measure the individual ester concentrations. I did sniff the beers though to get a general idea of whether the hybrids are actually fruitier than the parent strains. The fermentations were done in wort that had only been hopped in the beginning of the boil, to make sure that the majority of the beer aroma was yeast- and not hop-derived.

minifermsThe small-scale fermentation vessels

fermentationFermentation progress

abv_ph ABV% and pH of the beers

As you can see, there was considerable differences in fermentation rate between the strains. Of the parent strains, Conan started fast, but ended slow, while WLP644 was the other way around with a slow start and faster finish. In early stages of fermentation, the H1 hybrid was also doing well, but in the end it was two of the meiotic segregants, H1/A4 and H1/C4, that reached the lowest final gravities after two weeks of fermentation (1.013 and 1.009 respectively). The Conan and WLP644 parent strains reached final gravities of 1.015 and 1.017 (this would probably have dropped slightly with a couple of more days of fermentation). There was considerable variation in pH as well, as the lowest pH values were observed in the beers fermented with H1/A4 (4.39), while the highest pH values were observed in the beers fermented with H2, H1/C4 and H1/H1 (4.64, 4.61 and 4.69). The aromas of the beers were very similar, all featuring a similar fruity tone that reminded me of various stone fruits (peach and apricot). While there were some differences in intensity between the beers, I’m not sure how much I would trust just my nose. In my opinion the strongest fruity aroma was found in the beers fermented with Conan, F1/A4 and F1/H1. The weakest aroma was found in the fastest fermenting beer, i.e. F1/C4. However, as I mentioned the actual ester concentrations would need to be measured to actually draw any conclusions. All aromas were ‘clean’, with no signs of any phenolics (both parents are POF-). The WLP644 beer had a slight sulfuric note to it though. Another thing I observed during these fermentations, was that WLP644 flocculates poorly, while Conan and all the hybrids flocculated quite well.

The next step will be to actually brew and taste some beers brewed with these yeast strains, in order to see if there actually is any real world difference. For this I was planning on brewing up a 25-liter batch of APA wort (OG around 1.050, IBUs around 50, whirlpool hops, but no dry hopping), which I would then split into 5 fermentation vessels. To these I would then pitch: Conan, WLP644, H1, H1/A4 and H1/C4. I’ll return when it is time for the brewday and ultimately the tasting notes.

References and additional reading for those interested:

Krogerus K, Magalhães F, Vidgren V, Gibson B. 2015. New lager yeast strains generated by interspecific hybridization. Journal of Industrial Microbiology & Biotechnology 42: 769-778. DOI: 10.1007/s10295-015-1597-6

Steensels J, Snoek T, Meersman E, Nicolino M, Voordeckers K, Verstrepen K. 2014. Improving industrial yeast strains: exploiting natural and artificial diversity. FEMS Microbiology Reviews 38: 947-995. DOI: 10.1111/1574-6976.12073

October 22, 2015
by suregork

Tasting Impressions: Schwarzbock from 2013

I found a couple of bottles of homebrewed Schwarzbock from 2013, and I decided to see how it had developed during two years in bottle. This one ended up at an ABV of 6.8% and with a final gravity of 1.020, so a bit lighter than what was originally planned. I remember this one being very tasty when fresh, so let’s see how it tastes now!schwarzbock

The beer pours black and with a fluffy tan-colored head (it looks a lot lighter in the picture below). If you hold the glass against the light, you see that the beer actually has a dark ruby color (and is crystal clear). As the head collapses, it leaves patches of lacing along the glass. A nice appearance! The aroma is really nice as well, and it features a good combination of chocolate-like roasted tones, together with dark fruits and caramel. There is a slight alcohol note in the aroma as well, even though this is only 6.8%. The flavor is mostly roasty as well, with tones of dark chocolate and ash dominating. Behind this roast, there are tones of malt bread, biscuits and caramel that balance out the flavor. There are not many hop-derived flavors, but that was expected based on the recipe and the beer age. The finish has a moderately light bitterness though. The finish is quite dry as well, which adds to the perception of a relatively light body. This is quite a difference to the sweet and strong imperial stouts. The moderate carbonation level gives the beer some more mouthfeel though. It is quite easy to drink, and it has aged very well! Overall, a very nice beer that I would definitely brew again!

October 18, 2015
by suregork

Homebrew: Fresh Hop Ale

I collected this year’s hop harvest two weeks ago, and today we finally brewed a beer with them. This is the first time I’m using homegrown hops, so am really looking forward to tasting the final beer! Technically, this wasn’t actually a fresh hop ale, since I dried the hop cones before using them – but I’ll call this a fresh hop ale anyways. Since I’m not sure about the alpha acid content of these hops, we decided to use them only as flame-out hops, and instead use some Herkules at the beginning of the boil. This way we will hopefully extract the maximum aroma out of them as well. The homegrown hops weren’t very aromatic, so I’m expecting mostly grassy flavors and less of the typical citrus and pine resin. But hopefully I’ll be positively surprised! The post-boil wort had a slight perfume-like tone, which might have been hop-derived. For the malt bill, we went with a very simple 90% Maris Otter and 10% Carapils to an OG of around 1.050. This should let the hops shine (if they do). For the yeast, we used a really fruity ale strain that I’ve developed at work (more about that in a future post). I’m hoping it will compliment the hops, and make for a refreshing and crisp fresh hop ale! We will see in a couple of weeks!


This was the first time we brewed at our ‘new’ basement brewery (we moved there 1.5 years ago – yes, we’ve been extremely slow with the renovation), and I’m happy to say that everything went really smoothly. We were done in 5 hours and 30 minutes, reached almost 70% brewhouse efficiency, and the ventilation system (a really powerful inline exhaust fan) worked amazingly well. Looking forward to brewing a bit more regularly from now on!

Recipe Details

Batch Size Boil Time IBU SRM Est. OG Est. FG ABV
24 L 60 min 57.8 IBUs 8.6 EBC 1.048 SG 1.009 SG 5.1 %

Style Details

Name Cat. OG Range FG Range IBU SRM Carb ABV
American-Style Strong Pale Ale 51 1.05 - 1.06 1.008 - 1.016 40 - 50 11.8 - 27.6 2.2 - 2.8 5.6 - 6.3 %


Name Amount %
Pale Malt, Maris Otter 5 kg 90.01
Cara-Pils 0.555 kg 9.99


Name Amount Time Use Form Alpha %
Herkules 26 g 75 min Boil Pellet 17.5
Homegrown 75 g 15 min Aroma Pellet 3


Name Lab Attenuation Temperature
Fruity Ale 77% 15°C - 23.89°C

October 7, 2015
by suregork

Homebrew: Wedding Dunkel

Time for another wedding beer. This time not for my own wedding, but for two of my friends’ wedding. The groom requested one dark and malty beer (the wedding is in January, so that would fit with the cold weather) and one pale and fresh beer. I’ve noticed that the most popular beers during events, where the majority of the people are not ‘beer nerds’, are balanced and easy-to-drink beers. American Pale Ales with a relatively mild bitterness seem to be especially popular, so I thought I’d go with a remake of my own Wedding APA for the pale and fresh beer. For the dark and malty beer, I decided to go with a dark lager.

I haven’t brewed many dark lagers before, but decided to go for a malt base dominated by Maris Otter and Munich malt. To this I added hints of Chocolate and Dark Crystal malt to give some color and flavor. I kept it simple with the hops, and decided to go with Tettnang at moderate amounts to a fairly low IBU. For the yeast I chose to use W-34/70, which is my favorite homebrew lager yeast because of the ease-of-use (just sprinkled two packs on top of the 21 litres of wort) and the clean and crisp flavor profile. The brewday went extremely smoothly, and 21 liters of wort are now fermenting strongly at 12C. The aroma coming from the airlock is really nice, which is always a positive sign! The wedding is in about three months, which will mean I will have some time to lager the beer once it has finished fermenting.

Recipe Details

Batch Size Boil Time IBU SRM Est. OG Est. FG ABV
21 L 60 min 20.1 IBUs 33.6 EBC 1.053 SG 1.012 SG 5.3 %

Style Details

Name Cat. OG Range FG Range IBU SRM Carb ABV
European-Style Dunkel 38 1.048 - 1.056 1.014 - 1.018 16 - 25 29.6 - 39.4 2.2 - 2.8 4.8 - 5.3 %


Name Amount %
Pale Malt, Maris Otter 2.7 kg 51.33
Munich I (Weyermann) 2.3 kg 43.73
Chocolate Malt 0.13 kg 2.47
Crystal 300 0.13 kg 2.47


Name Amount Time Use Form Alpha %
Tettnang 30 g 65 min Boil Pellet 3.8
Tettnang 15 g 35 min Boil Pellet 3.8
Tettnang 15 g 4 min Aroma Pellet 4.5


Name Lab Attenuation Temperature
Saflager Lager (W-34/70) DCL/Fermentis 75% 8.89°C - 15°C

October 3, 2015
by suregork

Homebrew: Bavarian Hefeweizen

I’ve again been lazy and haven’t updated the blog for a while. There hasn’t been that much interesting to post though. About three weeks ago I brewed a Bavarian Hefeweizen for a friend, and today I decided to pop the first bottle as quality control. The recipe was really simple, with the malt base being 60% wheat malt and 40% pale ale malt. I hopped with Tettnanger to a modest 16 IBU, and fermented the wort with WLP380, supposedly the Schneider Weisse yeast.

Recipe Details

Batch Size Boil Time IBU SRM Est. OG Est. FG ABV
20 L 60 min 15.6 IBUs 9.2 EBC 1.048 SG 1.010 SG 4.9 %

Style Details

Name Cat. OG Range FG Range IBU SRM Carb ABV
South German-Style Hefeweizen 66 1.047 - 1.056 1.008 - 1.016 10 - 15 5.9 - 17.7 2.2 - 2.8 4.9 - 5.6 %


Name Amount %
Wheat 3 kg 60
Pale Malt, Maris Otter 2 kg 40


Name Amount Time Use Form Alpha %
Tettnang 20 g 60 min Boil Pellet 4.5
Tettnang 20 g 15 min Boil Pellet 4.5


Name Lab Attenuation Temperature
Hefeweizen IV Ale (WLP380) White Labs 77% 18.89°C - 21.11°C



The beer pours with a hazy golden-yellow, almost grey, color. A fluffy white head is formed, but it collapses a bit too quickly for a Hefeweizen. A typical wheat beer appearance. The haze is both yeast- and protein-derived as it was quite clear before I put it in the fridge.

The aroma is typical Hefeweizen, with tones of cloves and banana. The spicy 4-vinylguaiacol dominates the aroma profile, but there are lots of fruity esters present as well. The aroma is quite one-dimensional, but I guess it fits the style quite well.

As with the aroma, the flavour profile is dominated by spicy phenols and fruity esters. The amounts of esters and higher alcohols almost go a bit too far as I get hints of solvent as well. On the other hand, it has only been three weeks since pitching, so these will probably subdue a bit with some time in the bottle. There are some malty and doughy tones hidden in the background, but I can’t detect much hop presence at all. As it should be in a Hefeweizen. The carbonation level is high and the body quite light. Refreshing and quite easy to drink.

Overall this is an okay Hefeweizen. I’m not that big fan of the style, so I have a hard time judging how successful this beer is. It is still very young, so it will probably change a bit with more time in the bottle. There are definitely a lot of esters and phenols present, as it should be, but there might even be a bit too much of them at the moment. Perhaps this could have been fermented at a slightly lower temperature?