Monthly Archives: June 2015

Homebrew: Wedding IPA – American IPA

Yesterday I brewed the fifth and final batch of beer for my wedding in August (see previous posts for the Wedding Pils, Wedding Blond, Wedding Hybrid, and Wedding APA): an American IPA loaded with hops and fermented with Conan. I’ve brewed a slightly similar recipe before (see here), and while it was a nice beer, it ended up a bit too sweet with WLP007. This time I’m changing up the hop bill slightly based on what I have in the freezer, and I’ll be fermenting the wort with Conan. I’m hoping for a hoppy and bitter IPA, with loads of fruity aromas from both the hops and the yeast.

The malt bill is similar to the APA I brewed last week, and it consists of Maris Otter, Munich, CaraPils and CaraAmber.  I mashed quite low (63C) in order to get a very fermentable wort. I’ve used Conan a couple of times before and I’ve ended up with around 78% attenuation. I aimed for an original gravity just below 1.070, in order to get a beer with around 7.5% ABV. For the hops, I chose to bitter with Herkules (using up the last from a 100g bag), added some Cascade and Centennial during the boil, and at flameout I added even more Cascade and Centennial together with some Amarillo. The bitterness levels should be around 70-80 IBU, depending on how much the whirlpool hops contribute. I pitched a 1.5L starter of Conan after I had cooled the wort down to around 20C. I placed the fermenter in my fermentation fridge and set the fermentation temperature to 19C. I checked the fermenter 24 hours later, and it was fermenting violently with krausen coming out of the airlock. After a quick clean-up things were looking good again. Man it was smelling good inside the fermentation fridge!

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Homebrew: Wedding APA – American Pale Ale

Today I brewed the fourth and penultimate batch of beer for my wedding in August (see previous posts for the Wedding Pils, Wedding Blond, and Wedding Hybrid): an American Pale Ale loaded with Cascade and Centennial. I’ve brewed variations of this recipe several times before (one, two and three), so I know exactly what to expect. The resulting beer should have a hop-dominated aroma, with tones of grapefruit, pine resin and floral perfume, while the taste should feature a lightly bready maltiness together with a citrusy and floral hoppiness that ends in moderate bitterness and semi-dry finish. All in all, it should be a really easy to drink, yet still flavorful beer. The beers have been crowd favorites in the past, so am predicting that this keg will be the first to run out during the wedding.

The malt bill is simple, consisting of Maris Otter, Munich and CaraPils.  These should, together with the relatively high mash temperature (67C) and low-attenuating yeast (WLP002), yield a solid backbone to the beer despite the low ABV%. I aimed for an original gravity just below 1.050, in order to get a beer with around 5% ABV. For the hops, I chose to bitter with Herkules (since I still have some left from a 100g bag), and at flameout I added a large dose of Cascade and Centennial. The bitterness levels should be around 40 IBU, depending on how much the whirlpool hops contribute. I pitched a 1.5L starter of WLP002 after I had cooled the wort down to around 20C. I placed the fermenter in my fermentation fridge and set the fermentation temperature to 18C. I like using ‘English Ale’ yeast in my APAs and IPAs, since I think the esters they contribute go well with fruity hops. The high flocculation is also a bonus. Hopefully this one turns out as tasty as my previous brews of this recipe.

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Physicochemical analysis of Sahti

Last summer, me and a couple of colleagues visited the 23rd National Championship in Sahti brewing, which was organized in northern Espoo. The purpose of our visit was not to compete or just drink Sahti, but rather we were there to collect samples for a research project: we had decided it was time that a thorough physical and chemical analysis on Sahti was to be performed.

First of all, what is Sahti? Well, Sahti is a traditional farmhouse beer that has been produced and consumed in Finland for centuries. The Sahti beers that I have tried have all been sweet and alcoholic, with strong yeast tones in the flavour. The aroma of isoamyl acetate (banana) has particularly stood out. If you are interested in a more thorough introduction, then you can head over to this blog. For instructions (in Finnish) on how to make your own Sahti at home, you can check out this blog.


© Nesster / Flickr

We collected samples from 12 random Sahti at the Championships (all from different parts of the country). We then did some thorough analysis on these samples, including: ABV%, residual extract, IBU, colour, foam stability, sugar profile, organic acid profile, higher alcohol profile, ester profile, phenolic acid profile, 4-vinylguaiacol content, and finally we looked for juniper-derived components with GC/MS. We also analyzed seven commercial beers as references (one Sahti, two Pale Lagers, two Hefeweizen, and two Porters).

There was quite a lot of variation between the samples, but in general the Sahti had quite high ABV%, residual extract and ester concentrations, as was expected. The isoamyl acetate (banana aroma) concentration was really high in some of the Sahti (up to around 14.5 mg/L). Since Sahti is unhopped or lightly hopped, the bitterness values were low. Also, since Sahti is typically uncarbonated or lowly carbonated, the samples had really poor foam stability. All samples also had 4-vinylguaiacol (clove-like aroma, typically found in Hefeweizens and Belgian-style ales) concentrations above the flavour threshold. This is a presumably a result of the use of Finnish baker’s yeast. It can be concluded that Sahti indeed is a unique beer style, with some very interesting properties. I’m not that big of a fan myself, but I can understand the fascination behind the style.

You can download a pre-print version (i.e. it hasn’t been formatted yet) of the publication here.


Sahti, a strong, unhopped farmhouse beer flavoured with juniper is still actively brewed in rural areas in Finland. Presented here is the first comprehensive analysis of the physical and chemical properties of this unique beer style. Twelve sahti samples from the southwest of Finland were analysed and while properties varied, the beers generally had high levels of alcohol (mean = 7.9% ABV) and high residual extract (mean = 9.5 °P). Foam stability was negligible, as is typical for the style, and glycerol concentrations at 3.1 – 4.7 g/l were higher than in reference beers (commercial lager, wheat beer and porter). Both of these features may be attributed to the very high gravity conditions employed in brewing sahti beers. Bitterness levels were relatively low (3 – 13 IBU) due to the absence or moderate use of hops. All samples contained detectable levels of the clove-like compound 4-vinylguaiacol due to the use of baker’s rather than brewer’s yeast for brewing. Concentrations of higher alcohols and esters were high, with many individual aroma compounds being above the normal flavour thresholds. Results have highlighted the uniqueness of this style of beer in comparison to commercially available beers and have contributed to our understanding of the reasons for the particular sensorial properties of this traditional beer style.

Homebrew: Wedding Hybrid – American Pale ‘Lager’

Today it was time to brew the third batch of beer for my wedding in August (see my previous posts for the Wedding Pils and Wedding Blond): an American Pale Ale-like beer, fermented with one of my newly created A62×C902 lager yeast hybrids. I’m not really sure what to expect from the beer, but I’m hoping for a really fruity aroma and flavour. Apart from the large amount of experimental fermentations we’ve done with the yeast hybrids at work, we have also fermented a bigger batch of ‘typical’ lager wort with one of the hybrids, which we then kegged and taste-tested. That beer at least had a really fruity flavour, with plenty of ethyl esters and isoamyl acetate. That wort was relatively lightly hopped, so it will be really interesting to see how the yeast aromas go along with a more heavily hopped beer. I’m hoping for bold flavours, yet still an easy-to-drink beer.

The recipe might seem a bit complicated, as it features six different malts and five hop varieties. This is because I’m using up some opened malt and hop bags. I’m hoping that the ingredients come together nicely, and that the flavours aren’t too muddled in the final beer. The malt bill consists mainly of some Pilsner and Maris Otter malt as base, with a hefty portion of Munich malt to lend some more breadiness. The rest of the malt bill consists of some CaraPils, oat flakes and Crystal 6oL, in order to give the beer some increased mouthfeel and a hint of caramel. I aimed for an original gravity of around 1.050, in order to get a beer with around 5% ABV. For the hops, I chose to bitter with some leftover Styrian Goldings and Simcoe, and at flameout I added a mixture of Amarillo, Citra, Saphir and Simcoe. I aimed to keep the bitterness levels quite low and instead concentrate on a massive hop flavor and aroma. I pitched a 2.5L starter of one of my lager yeast hybrids after I had cooled the wort down to around 17C. I kegged the Pilsner yesterday (it was tasting awesome by the way!), so my fermentation fridge was free again. I set the fermentation temperature to 15C, and 6 hours after pitching there was already slight activity in the airlock. Fingers crossed that this turns into an awesome beer!

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Report from the 35th European Brewing Convention Congress

I recently attended the 35th EBC (European Brewery Convention) Congress in Porto, where I held both an oral presentation entitled ‘Newly-created hybrid lager yeast strains (S. cerevisiae x S. eubayanus) outperform both parents during brewery fermentation‘ and co-authored a poster entitled ‘Non-conventional yeast as a new tool for beer flavour modification’. I’ve already written two blog posts on our new lager yeast hybrids (see here and here), so I won’t go into details on that topic here. However, here is a link to my presentation slides in case you are interested. I more or less go over the data from our recent publication, but it should hopefully be presented in a way that is easy to follow.


The topic of our poster, i.e. the use of non-Saccharomyces yeast in brewing for increased flavour, should be a topic that is interesting for many experimental homebrewers. You can download a copy of the poster here. We did small-scale wort fermentations using 13 different non-Saccharomyces yeast species, and 3 Saccharomyces yeast species as controls. We then analyzed the concentrations of higher alcohols, esters and 4-vinylguaiacol in the resulting beers, and identified yeast species that 1) produced high amounts of esters, but 2) were also POF- (i.e. they didn’t produce 4-vinylguaiacol above the flavour threshold). This was because we were interested in applying these yeasts to beer styles where a spicy, phenolic and ‘wild’ flavour isn’t wanted. Some interesting yeasts were Kazachstania servazzi, Naumovia dairenensis, Lachancea fermentati , and Kluyveromyces marxianus.


Many of the non-Saccharomyces yeasts were quite poor at fermenting wort (with its complex mixture of sugars and with the resulting high concentrations of ethanol), so we had the idea of using them in co-fermentations together with an ale yeast strain. To maximize the flavour contribution from the non-Saccharomyces strains, yet still ensure proper attenuation from the ale strain, we first pitched only the non-Saccharomyces strain, and added the ale strain after 24 hours of fermentation. We brewed three 30 liter batches, one control with only the ale strain, one co-fermentation with Kazachstania servazzi, and one with Naumovia dairenensis. We bottled all three batches and had the beer analysed. The beers co-fermented with the wild yeasts had significantly higher level of esters than the control beer, and had a strong fruity and floral aroma.

Finally, I thought I’d do a quick summary of some topics that could be relevant for homebrewers:

  • The ‘kettle hop aroma’ mystery, Praet T et al.

I missed this presentation myself, as it was parallel to the session I was having a presentation in, but I’ve seen a variation of this presentation at an earlier brewing congress. They have revealed that oxygenated sesquiterpenoids are formed during wort boiling from hop oils, and that these give the beer ‘spicy’, ‘woody’ and ‘hoppy’ notes. So these are hop aromas that require boiling, and cannot be achieved from dry hopping.

  • Protein thiols and sulfite, Lund M et al.

Protein thiols and sulfite can act as antioxidants, and their presence in beer can improve beer flavour stability. They noticed that the concentrations of these in wort can be increased by supplementing proteases to the mash. Protease supplementation also increased the flavour stability of the resulting beers. Perhaps flavour stability can be improved by optimising the mashing conditions (e.g. utilizing the proteases already found in the malt)?

  • Genetic metabolism of hop terpenoids by yeast in beer, Tristam P et al.

I missed this presentation myself, so am going only by comments from my colleague and the abstract. Apparently they have looked at how various hop essential oil compounds are metabolised by the yeast during fermentation. They found that the ATF1 gene is required for the biotransformation of linalool and geraniol to their acetate esters, and the OYE2 gene is required for the biotransformation of geraniol to citronellol. This means that different yeast strains (depending on their genetic background and the activity of the corresponding enzymes) may produce beers with different hop aroma profiles!

  • Influence of dry hopping on changes in the key aroma compounds of pale lager beer, Stingl S et al.

They had studied how various hop compounds are transferred to the beer during dry hopping, and looked at how the ratio of linalool to myrcene in the beer affects the aroma. Apparently the transfer of linalool to beer is very rapid during dry hopping, with maximum concentrations reached within an hour. Myrcene transfer is much slower, and it takes several days to reach the maximum concentration. At high concentrations, myrcene is thought to have an unpleasant aroma, so a short dry hop time (e.g. 1-4 days) might actually be preferable.

  • A high throughput monitoring of phenotypic changes in Brewer’s yeast during serial repitching, Kocar N et al.

They had done some studies on what physiological, genetic and proteomic changes occur during serial repitching. They did 16 repitching cycles at industry-scale and 31 repitching cycles at laboratory-scale, and it seems like you can repitch around 15 times without any big changes in physiology, karyotype or proteome. So don’t be scared to reuse your yeast a couple of times (this requires good sanitation practices of course)!

  • Beyond iso-alpha acids, Shellhammer T et al.

They studied how oxidized hop acids and hop polyphenols affect the IBU value and beer bitterness. They notices that oxidized alpha acids, i.e. humulinones, that transfer from the hops to the beer while dry hopping, not only affects the IBU value of the beer but also the perceived bitterness. They are perceived as less bitter that iso-alpha acids though. Some commercial heavily dry-hopped beers even had higher bitterness contribution from the humulinones than the iso-alpha acids. So dry hopping does increase bitterness!

  • Bitterness impact of common brewing spices, O’Neill C et al.

They studied how various common brewing spices affected the measured and perceived bitterness. Especially cinnamon seems to increase IBU and perceived bitterness. Coffee beans and coriander also seem to increase the perceived bitterness. So keep that in mind when adding spices to your beer!

  • Aroma contributions from Simcoe and Hallertau Mittelfrüh hops to beer using different hopping regimes, Sharp D et al.

They had looked at and compared how different hopping regimes (kettle hopping, whirlpool hopping and dry hopping) and two hop cultivars (Simcoe and Hallertau Mittelfrüh) affect the perceived aroma and concentration of various hop oil compounds in the beer. For a homebrewer, it was no surprise that Simcoe gave more tones of tropical fruit, citrus, stone fruit and pine compared to HM. Dry hopping and whirlpool hopping seem to give similar effects, which is something to keep in mind when planning your hop schedule.


There were probably many more interesting presentations (and I decided to leave out the posters from here as well), but unfortunately I wasn’t able to see them all due to the triple parallel sessions during the conference. All in all it was a very interesting conference with lots of interesting researchers and research topics! Already looking forward to the next one! Please leave a comment if you have any questions, and I can try to answer them as best as I can.

Homebrew: Wedding Blond – Belgian Blond

I just came back from the 35th EBC Congress in Porto, where there were some really interesting presentations and posters. I’m currently writing up a post with a summary of the topics that are relevant to homebrewers, and I should hopefully have it ready during next week! Today I also brewed the second batch of beer for my wedding in August (see my previous post for the Wedding Pils): a Belgian Blond based on a recipe I brewed almost three years ago. The beer I brewed then was light, hoppy and featured some nice esters and phenolics from the yeast in the aroma. Should be perfect for a warm summer day, perhaps together with the seafood on the menu.

The recipe is quite simple, featuring a malt bill of mainly Pilsner malt, with just hints of flaked oats and cane sugar, to contribute some more mouthfeel and dry out the beer. I aimed for an original gravity of around 1.050, in order to get a beer with around 5.5% ABV. For the hops, I again used Herkules for bittering, but instead added some Styrian Goldings and Saphir towards the end of the boil. I pitched a 1L starter of WLP530 (Abbey Ale) after I had cooled the wort down to around 20C. My fermentation fridge is still occupied by the Pilsner, so chose to ferment this at room temperature. This should help bring out some yeast tones in the aroma as well. I placed the fermenter in a slightly colder room (~ 18C), but I imagine the wort temperature will rise to about 23C during active fermentation. I checked the fermenter 5 hours after pitching and there was already rapid bubbling in the airlock meaning that the yeast was already chewing through the sugars. Another smooth brewday!

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