2013 Summary and 2014 Prospects

I finally had a day free and decided to try and write another post. I’ll focus on what’s been happening this past year and what will happen in the next one.

As you all have no doubt figured out, my PhD project has completely taken over my life, leaving no time for brewing or yeast ranching. Unfortunate as it is, it is also a very exciting time in my life full of both good and bad things.

Let’s recap what happened in the year 2013.

– First and foremost I want to apologize for not keeping the blog up and not answering emails. I honestly was so busy these last few months that I forgot about it completely and haven’t checked my email since around November. Yesterday I logged back in and found 182 emails from yeast enthusiasts asking me about yeast. I really feel terrible, guys. I’ll try to get back to as many of you as I can as soon as I can. Feel free to email me again just so that your letters are at the top of the list.

– Secondly, the response to the Cantillon Iris isolates has been overwhelmingly positive. Not only from around a hundred homebrewers, but professional brewers as well. Cory King of Perennial Ales and Side Project liked C1 strain enough to use it in a commercial batch and sent me a very nice gift package with his beers, including one made with C1, accompanied by a very warm letter saying he liked it so much he may make it his house Brettanomyces strain. Thank you Cory! You’re indeed a master of your craft and your beers are reserved as my “special occasion” beers and never disappoint. Brandon Jones of EmbraceTheFunk also made some beers with Yazoo Brewing which were released last year and seemed to have had a positive feedback. I didn’t actually imagine that my isolates would be used in commercial production at the time of isolation so this is really cool!

– Thirdly, some months ago I was contacted by the BeerAdvocate magazine regarding an interview for an article they were writing about homebrewer yeast ranchers. The article came out in the August issue and brought several new readers to this blog. I have enjoyed many a conversation with fellow yeast enthusiasts as a result and was able to help a few guys set up home labs.

– Fourthly, as many of you know, sometime around June last year I have finally managed to get my PhD project off the ground and it took off nicely. Just one of the hazards of starting your own project rather than directly continuing someone else’s experiments – it takes for ever to get things to work! After some snags along the way, I managed to optimize the experiments by September and it really took off. Working 7 days a week didn’t leave much time to do any brewing or ranching so I reserved to reading articles about beer and trying to post a couple Beer Science Reviews which were also received very well by the readers.

– Fifthly, I had a surgery in December and that took me out of the beer scene even further for a while. Everything went well, except for some letters from my insurance company informing me that they decided to cover just a tiny portion of the costs and apparently stuck me with an 18 thousand dollar debt. Happy holidays!

This should about sum up my adventures of 2013. Though it may not seem like a very busy year, it was both in terms of yeast ranching as well as other things. Site views went from around 14.6 thousand in 2012 to just over 61 thousand in 2013 though I don’t much care for how many people visit the site as long as at least some of them find my writing helpful. I strive to occupy a very small and specific niche in the homebrewing scene that is not very popular in the overall scheme of things simply due to its laborious, scientific and just technical nature and so don’t expect to ever be even remotely as popular as straight brewing and hop blogs. I’m not the only scientifically inclined homebrewer nor am I the only one who writes about his adventures in this field. We are few, we all know each other, and we help the homebrewing community little by little, often unrecognized, just like the scientists that we are. In any case, I would encourage my beer brothers to not be scared away by yeast and the amazing world of kitchen microbiology and give it a go. It is a wonderful adventure if you chose to take that road!

What’s going to happen in 2014?

The most important event is that I’ll be leaving Brooklyn and New York City altogether. Why? For Science! Our entire lab, including the staff and students is moving to SUNY Upstate Medical Center in early March 2014. It is located in Syracuse, NY which in a way takes me very close to my roots because I spent several years in that area as a boy and finished high school in a tiny rural school not too far from Syracuse. My graduating class was something like 16 people. Yes, the school is that small. What does that mean? It means that my life is very crazy right now. Between apartment hunting, getting the lab ready to move, working on my own project and other things, I have no time for absolutely anything at all. I will try to push out one more yeast release before leaving in March, but for a few weeks after that don’t be surprised to see no activity from me at all.

I will have to set up all my beer and yeast gear anew at the new place. Taking my bookshelf hood with me is not a viable option so I’ll have to make a new one. This may actually be a positive thing because I envision it as a sort of a small portable yeast ranching hood which may be more appealing to my readers rather than a stationary one and help them on the yeast ranching journey.

Do I actually plan to continue with homebrewing and yeast ranching? Absolutely! If anything, the move should give me plenty of free time because there is absolutely nothing to do in Syracuse and there is only so much science you can do every day before you start burning out. My prospective roommate, who is also my friend, coworker and a fellow student, is very sympathetic to the idea of having an unlimited supply of beer. There are also whispers of homebrewing professors up there as well, and I’ll have to investigate it further. Hopefully 2014 will be very productive and I’m looking forward to seeing what it brings.

I do hope there is a homebrewing store up there, preferably in the city since I do not anticipate having a car. I also hope to meet some of the local homebrewers and expand my brewing horizons over the approximate 3+ years I will be living there. If anyone knows anything about the homebrewing scene there, please let me know.

Wishing you have a very malty and hoppy year!


Side by Side Cantillon Brett Tasting

It’s been a very long time since my last post. Lately I’ve been even busier than before, which is not unexpected for someone in my position, and homebrewing as well as yeast ranching has, for all intents and purposes, ceased to exist for me. I have been reduced to reading blogs and fantasizing about homebrew over the last few months because I can’t take part in it in real life on account of working seven days a week. Though I have full intentions to brew and make new plates to isolate more goodies, my last brew day was in the spring. Even on weekends I’m stuck in the lab glued to a microscope, dissecting newborn mouse eyes. The situation may be changing as enough eyes have been collected to keep my experiments rolling for at least a few more months. Hopefully, soon enough I’ll start brewing and isolating bugs again.

One of my readers asked for a side by side tasting of the BK C strains and it sounded like a good idea. Besides, I wanted to do this for a long time so thanks for the encouragement.

Left to right: C1-C2-C3

Left to right: C1-C2-C3

The recipe for these beers is simple:


US 2-Row Malt 80.0 %
US White Wheat Malt 20.0 %

Mashed at 147˚F.  OG – 1.056. FG – 1.001.


German Tradition
1.00 oz
60 Min From End

US Calypso
2.00 oz
5 Min From End

US Calypso
1.00 oz
At turn off

Left in primary for 3-5 months and bottled with table sugar to ~3 vol.


I have tasted these beers before and gave some descriptions here and there, but never all together and never with a few months of age on the bottles. So let’s see how they are doing.



Appearance: Orange/yellow. Clear with just a little bit of haze. Medium head in beginning, but then recedes to a ring around the glass. Lively carbonation.

Smell: Woody funk in the foreground, followed by sweet, fruity notes. Ripe pineapple and citrus. Allowed to stand and breathe a little, the woody funk goes down and sweet fruitiness becomes more prominent.

Taste: Whoa, it changed a lot since last time I tasted. Initially there is no woody funk at all, and the flavor is malt forward. Barnyard, earthy, wet funk makes an appearance and is almost instantly washed away by carbonation to be replaced by lemon, hay, and woodiness. Lemon and woody funk fight for dominance with lemon being the victor in the end and lasting through the finish. If I didn’t know this this has never even touched wood, I would argue that this beer was barrel aged for too long due to really woody-barrelcharacter. Very dry and just a little tart. Enough to make my mouth water. A bit vinous, like dry white wine. Citrus, citrus, citrus.

Mouthfeel: Medium. Surprising for such a dry beer, but it’s by no means thin. Mouth filling, even somewhat coating.

Overall: This beer has improved a lot. Rather than weird woody funky fruity beer with individual characteristics not really playing harmoniously, as was the case just a few months ago, I feel like now it’s a much better brew. Things just work, and work well. There is too much woodiness for me, but otherwise it’s a very pleasant and refreshing beer. Perfect for the summer. I’m really interested to see how it continues to develop.


Appearance: Yellow/orange, much like C1, but brighter. Clear with a little haze. Champagne-like carbonation with a lot of head at first, but then goes down with nothing remaining, just bubbles coming to the surface.

Smell: Woody funk, but much less pronounced than C1. Grassy, sweet, fruity, apricot. More appealing to me than C1.

Taste: Also quite different than it was the last time. Malt forward, very subdued woody funk that lets fruitiness and even what seems like sweetness to come through. I’m sure I can taste just a hint of strawberry on the overall fruity background here and there. Dry and vinous, tart, but less so than C1. Woody funk comes back in the end and gets replaced by hop bitterness.

Mouthfeel: Fuller than C1. I noticed before that C2 seems to produce almost an oily mouthfeel and this is the case. It’s almost oily, almost velvety, just strange for such a dry beer.

Overall: Not as refreshing as C1, but interesting nonetheless. It’s pleasant, and the absence of dominating woodiness is a big plus.


Appearance: Straw yellow and crystal clear. Initial head recedes to nothing, same as C2.

Smell: Similar to C2 in terms of less woody funk, but more herbal, grassy, Cantillon-like. Does not smell sweet, though one can still detect pineapple notes.

Taste: Fruit forward. Sweet, pineapple, white apple, general fruitiness. Woody funk makes a sudden and strong appearance and disappears leaving light bitterness and gentle woodiness behind. Probably the least woody of the three beers. Tart, dry. For some reason really makes me think of big, juicy, sweet white apples. Funk comes back in the aftertaste.

Mouthfeel: Light. Lighter than C1 or C2.

Overall: Interesting. Not bad, but I feel like it needs more age. Fruity.


It’s intriguing that they changed as much as they did and I’ll be sure to give them another official tasting maybe in a year or so. Overall I’m pleased with the way they turned out. Stay tuned for more posts coming in future!

Sending Out Cantillon Iris (2007) Brettanomyces C1

Hello, my yeast mates!

The time has come for another yeast mail out!

This time it’s the Cantillon Iris (2007) Brettanomyces C1 strain.

Some information about this strain:

Ferments relatively fast to around 1.010 after which it slows down to a crawl. In my experience it fermented from 1.052 to 1.001 in 3.5 months resulting in 97% attenuation. It forms a pellicle very quickly. Pellicle is bright white and thick with large bubbles, but after a while it thins out and becomes patchy. The smell and flavor profile based on my experience as well as of those who got it from the October 2012 yeast mail is that it’s a pleasant strain which can be used as the primary strain. One of the people took first place in a competition with a beer that was 100% C1 fermented.

My impressions were as follows: Incredibly sweet smelling, strong fruity smell with apples, pears, mangos, honeydew, lots of honey, elderflowers, just general non-specific flowers and fruits, wood, hay, Bretty funk. Easily one of the best smelling beers I’ve made. Very dry and lightly tart with a hint of lemon. Since Brett thins out the beer and makes hops stand out like mad I’ll have to wait a few more months for an official tasting until the 1oz Callypso bittering hops fade enough for a Saison to not taste like it’s 1000 IBUs.

Other people who tried it and got back to me reported it being generally fruity and lightly tart with mostly apples, pears, lemons, wood and Brett funk.

As before, should your beer turn out horrible or poisonous because of this strain it’s not my fault and you are using it at your own risk. Also by using this strain you agree to give me feedback about it and possibly even send me a bottle of the resulting beer.

There are 23 vials available with around 25 billion cells each. If you get a vial and plan to use it as the primary strain, make sure you pitch at least twice the amount of yeast that you would with normal brewer’s yeast.


Email me at bkyeast@gmail.com if you’re interested in acquiring a vial. As before, it’s $10 for the shipping and all that other good stuff. If you have some cool and unique strains of yeast or some cool beers, feel free to let me know and we could work out a trade.



I will try to release a strain every month from now on so if you don’t get it this time there will be several other unique strains in the future.

Homebrew Alley VII Homebrewing Competition

Hey everybody! Remember me? That yeast rancher from Brooklyn, NY? Yes, that one! Well I’m still alive and kicking! I apologize for the long hiatus in posting yeast experiments, but the truth is that I’ve been just too busy in lab. With grants due in a couple days there has been quite a push to come up with ideas and preliminary data to test them. Since the primary aim of this particular grant is my thesis project, I hope you can understand how it takes precedence over brewing and yeast ranching for the time being. Hopefully after submitting it this week things should get back to normal and I’ll no longer slave away until 10-11pm every day and will have time to brew some beers and ranch some yeast. The next yeast experiment is already planned out and will probably be posted in about a week for the benefit of a portion of my readers who have been asking me to do it for some time now. Until that sweet time comes I’ll try to entertain you by telling you how my first homebrew competition since 2011 went.

This year Homebrew Alley had over 700 entries, making it the biggest one yet. I picked it because it was local and there was no need for shipment as long as I paid the entrance fees and dropped the bottles off at the appropriate location. As you probably know, I always refer to competitions as a waste of beer and money because of my previous experiences with oxymoronic comments from judges (like the famous “dry and cloyingly sweet”) as well as just plain wrong statements such as describing Brettanomyces character of beers that have never been touched by Brett. This year I thought I’d give it another try mainly to see what people think of my sour brews. To my surprise, my Berliners ended up taking 1st and 3rd places in the categories entered. Another surprise was the scores for the Witch Poison Gruit. Though it received the lowest score I’ve ever gotten, it was nice to see that the judges accurately identified its characteristics, which they thought to be fermentation flaws, but instead came from the ingredients. To me that shows that this time people judging the beers were competent and didn’t just make things up.

Rather than posting the photos of the score sheets I’ll just give you the text because some of them are written in extremely illegible hand or just cut off mid-sentence.

So, on to the scores!


Not sure why they sent me two 3rd place ribbons.

xxxx = can’t be read without a cryptologist.


Berliner Weisse

Entered in Category 17 A


Judge #1:

Aroma: Moderate sour aroma (both lactic and slight acetic). Moderate leather, hay – nice. Complex. No hops. 9/12

Appearance: Pale yellow. Very slight haze. Pours with very low white head that dissipates immediately. 2/3

Flavor: Aggressive, but not overpowering sourness, mostly lactic. Bone dry. Mild Bretty barnyard flavors. Hints of wheat and honey in background. No hop flavor. 16/20

Mouthfeel: Effervescent, very prickly, no astringency or warmth. 5/5

Overall Impressions: Excellent Berliner. Maybe a little big for the style, but delicious. 8/10

Total: 40/50


Judge #2:

Aroma: Very mild sourness. Mostly lactic. Allows some wheat to shine through too. No hops. Some barnyard xxxx in there too. 8/12

Appearance: Pale golden. Opaque. Very slight white head xxxx energy and fades quickly! 2/3

Flavor: Sharp sourness – very lactic with supporting horsey and barnyardy. No fruit or yeast character evident. 16/20

Mouthfeel: Super light body. Low carbonation level. Dry as heck! No booziness. 2/5

Overall Impression: Undercarbonated for the style. More would have made it livelier. A little more general “funk” than a Berliner typically has. But this is a very tasty Berliner. Should get even better with age. Thanks for entering! 7/10

Total: 35/50


Final Assigned Score: 37.5

Place awarded:  3rd


My thoughts: It’s interesting how two people drinking the same beer differ in carbonation description. It was also a little surprising to see that it’s aggressively sour because I always thought of it as very mild.


Troubadour (Berliner with raspberries)

Entered in Category 20 A


Judge #1:

Aroma: You can smell the sour as it pours. Tartness dominates, followed by a hint of “stinky feet”. Raspberry in the back (very true to life raspberry at that). Slight petrol behind, which is complementary. 10/12

Appearance: Pours with large head that rapidly disperses to film on top, clear, light pink/straw color. 3/3

Flavor: Sour tartness dominates. The raspberry flows behind. Otherwise clean lactic strong. Petrol notes towards end compliment. Some barnyard character as well. 17/20

Mouthfeel: High carbonation, light body, puckering, dries out. 5/5

Overall Impression: A delightful beer. The level of tartness is on the higher end of the spectrum for a Berliner and also has a nice depth. Displaying nice lacto as well as Brett character. This might be intense for some, but I love it. Beautiful job! 9/10

Total: 44/50


Judge #2: actually same person as Judge #1 from Berliner Weisse

Aroma: Strong grainy wheat aromas accompanied by a touch of green apple-like sourness, a touch of acetic acid and a hint of raspberry. Slight phenolic. No hops. 10/12

Appearance: Pours fairly clear. Salmon color with a tall white head that dissipates quickly. 3/3

Flavor: Wheat apparent along with an aggressive sourness (combo lactic and acetic, more lacto). Mild plastic phenolics. Raspberry barely perceptible, but there. Hops not apparent – good. 17/20

Mouthfeel: Medium body (maybe a bit high for the style). Very highly carbed – nice. Mouth puckering, prickly. 4/5

Overall Impression: Very nice Berliner. Could use a touch more raspberry. Maybe a little big for the style. 8/10

Total: 42/50


Final Assigned Score: 43

Place Awarded: 1st


My thoughts: Never expected this! When I brought this brew to a homebrew meeting and people gave it very positive and enthusiastic reviews I thought they were just being nice. I guess this really is a successful combination. Now I just don’t have an excuse to not make this again!


Schismatic Dubbel

Entered in Category 18 B


Judge #1:

Aroma: Raisin, stone fruit, malt sweetness, restrained hop character. Sweet fruity ester character from yeast is very restrained. 9/12

Appearance: Pours with a thick, tan, airy head. Reddish-brown color. Clings to glass very beautifully. 3/3

Flavor: Salted caramel sweetness is dominant. Fruity yeast characteristics are very pleasant and has a strawberry quality to it. Alcohol warming is very noticeable at end (and on breath afterward). Toffee is dominant. 15/20

Mouthfeel: Medium body with medium-high carbonation. Initial creamy texture which leads to an alcohol warmth and slightly chewy. 4/5

Overall Impression: Very well executed beer in terms of style. However, alcohol warmth could be toned down just a touch and you may want to experiment with slightly less caramel malts. I really enjoyed this beer. 7/10

Total: 35/50


Judge #2:

Aroma: Big malty nose with some toffee notes and a little clove. 8/12

Appearance: Dark amber color with beige head. Great retention. Fairly clean. 3/3

Flavor: A lot of toffee + caramel. Very malty. Some raisins + phenols. Nicely balanced. Whole lotta toffee! 10/20

Mouthfeel: Medium-full mouth. High carbonation. Creamy. No alcohol warmth. 4/5

Overall Impression: Good example, but it falls a little flat in the end. 6/10

Total: 31/50


Final Assigned Score: 33

Place Awarded: none


My thoughts: This is not bad for a dubbel brewed in 2010 I think! Interesting how they differ in terms of alcohol warmth. Sounds like I should try recreating it.


Witch Poison Gruit

Entered in Category 17 E


Judge #1: Non-BJCP

Aroma: Big smokiness xxxx. Light cooked vegetables. Cabbage aroma. Some baby diaper, tons of diacetyl. Malt aroma – low to none. 3/12

Appearance: Golden. Hazy billowy head. Fizzy like soda. Head disappeared quick. 2/3

Flavor: Sharp sourness with Bxxxx smokiness. Smoke is peat-like with some bacon. Tart. Not a ton of malt. 7/20

Mouthfeel: Med-low boon. No astringent. No alcoholic. Tart. 3/5

Overall Impression: Unfortunately the diacetyl and smoke in this beer make it hard to drink. It is complex, just not the right kind of complexity. 5/10

Total: 20/50


Judge #2:

Aroma: Slight fishy aroma and a xxxx dominant cherry wood smokiness. No hop aroma. 5/12

Appearance: Pours orange-gold with thick head that dissipated almost immediately. Cloudy, but appropriate for style. 2/3

Flavor: Very complex, with smokiness and somewhat unusual fermentation characteristics. Strong lactic tartness, appropriate, but (not sure what happened here. he just cuts off) 8/20

Mouthfeel: Light body and medium carbonation. No alcohol warmth or astringency. Very strong and lingering slickness from lacto and diacetyl. 1/5

Overall Impression: Very strong lactic taste, but not very refreshing. Need to clean up the lactic off flavors (smokiness, fish) and reduce the slickness (probably combination of lacto and diacetyl) 4/10

Total: 20/50


Final Assigned Score: 20

Place Awarded: none


My thoughts: This is the lowest scoring beer I’ve ever had, but despite that I am strangely happy about it. The judges described it pretty accurately, but didn’t know that it’s all not fermentation flaws, but derived from the ingredients themselves. Smokiness, fishiness and bacon are contributed by a huge amount of peated malt. Vegetative character is contributed from the juniper branches, pepper and lemongrass. Slickness is probably from the rye. In any case I agree with them that the vegetal smell isn’t very appealing. It also looks like my suspicions about using rye and darker malts in a no-boil beer is not a good thing. Something in them doesn’t play nice with the bugs. Don’t know what to make of diacetyl as I haven’t noticed it. It probably wasn’t the best idea to enter it is a Gueze, but I just didn’t know where else to stick it. All in all this beer is what it is and they got it pretty much right. Most important thing is that I enjoy it in the summer, and strangely, so does my mother who hates beer.


There you have it. Looks like my Berliners are better than I thought and this gives me more incentive to continue with funky and sour brews.

As I mentioned before, I am still very much alive and intent to keep homebrew funky yeast science going strong. In recent days I’ve been getting more emails asking about the Cantillon Iris isolates as well as whether or not I’ve isolated some new strains. The answer is a definite YES. There will be more Iris strains in upcoming weeks and there will be more unique bugs isolated soon too. Hopefully after this week I’ll be able to get back to it.


Cascade Kriek Bug Isolation Part I

Greetings, fellow yeast mates!

First of all I’d like to wish you all happy holidays and I hope the New Year will bring you all only joy.

As the last post of this year I thought I’d do a little progress report on bug isolation from dregs and even beers that some of you were nice enough to send me.

I think of most interest to you will be the progress of Cascade Brewing Barrel House dregs because of the Lactobacillus brevis strain that they inoculate their beers with. Even though L. brevis is commonly thought of as a hop resistant species that produces aggressive acidity in beers it isn’t exactly right and some strains of L. brevis are killed by hop acids. Genetics of lactic acid bacteria hop resistance are interesting and are not bound to a particular species, but that will be discussed in a future post, which I’m already working on. In any case let us see what’s been happening at the lab these last few weeks.

Cascade Kriek

From their website: Our Kriek spends over six months in lactic fermentation and aging in oak barrels. This NW style sour red ale is fermented for eight months with fresh whole Bing and sour pie cherries.

Those who have had it will know that it’s very sour and aggressive. Actually when I had it before I became interested in reculturing and thus just poured away the dregs, I thought my tongue and tooth enamel were dissolving with every sip. Sounds like a very good source for that particular Lactobacillus strain, doesn’t it? Luckily, ‪Ryan Wagner from KROC (Keg Ran Out Club) had a culture of it growing in his yeast ranch and was kind enough to send some during the Cantillon Brettanomyces sharing event. Per his description, the culture was maintained at practically ideal conditions for Lactobacillus maintenance and produces a clean, strong and bright lactic character in wort within just a few weeks after inoculation with flavors and smells reminiscent of apricots. It was really exciting to get my hands on this culture because it sounded very promising. Shortly after receiving the culture I streaked it on some plates and took a peak at it under microscope. It was immediately apparent that the sample is practically loaded with Brettanomyces. This was a little strange since, as far as common knowledge goes, they do not use Brett in most of their beers. I contacted Ryan the same day and he confirmed that the culture contains only whatever was raised from the Kriek dregs. After that I contacted Brandon at Embrace the Funk since he asked to keep an eye out for Brett in Cascade beers because their flavors seem too “bretty” to be just regular Saccharomyces. He was not very surprised and said that Chad Yakobson also saw Brettanomyces in Cascade beers and this confirms it. The only logical conclusion as to the origin of this yeast in the beer then would be that it’s wild and got there from the barrels or the cherries used during fermentation and aging.

Micrograph of the Cascade Kriek culture. This definitely looks like Brettanomyces to me.

Micrograph of the Cascade Kriek culture. This definitely looks like Brettanomyces to me.

After a few weeks on different agar plates I ended up with three types of colonies that you can see below in the 12-3 o’clock portion of the MYPG+BG+p-C plate. These colonies look much better on other agars, but I’ll refrain from telling you about those for now for the sake of staying on topic. One seems to be Brettanomyces – medium to large, round, glossy, convex colonies. Another looks like Saccharomyces – round, flat, and matte. Perhaps it’s just some contaminant because those are very rare. The third looks like Lactobacillus – small, irregular/filamentous, colorless/off-white/yellowish. Each organism was inoculated into a small primary culture and will be used later to raise bigger ones.

MYPGBGp-C plate with various cultures streaked in quadrants.

MYPGBGp-C plate with various cultures streaked in quadrants.



While looking at yeast is fairly straightforward, looking at bacteria is a lot more difficult. These organisms are a lot smaller and my usual 600x magnification doesn’t suffice at all. They are so small and there is so little to them that the light just goes straight through and around the cells, making them difficult to see and requiring some playing around with the light, the condenser and the light filters on occasion. Here you can see micrographs taken at 1500x magnification, which is 2.5 times greater than that at which I usually take yeast pictures. They still look smaller than yeast at 600x so imagine just how tiny these guys are. Staining also helps a great deal. Compare the images of unstained and methylene blue stained cells and what difference in viewing it makes.

Unstained Lactobacilli

Unstained Lactobacilli

Methylene Blue Stained Lactobacilli

Methylene Blue Stained Lactobacilli

While I was at it, I also took some high power images of the Brettanomyces from this culture and even captured a short real-time video where you can see what I think are vacuolar granules or fat globules moving inside the cells and me playing with the focal planes a little bit.

Cascade Kriek Brettanomyces

Cascade Kriek Brettanomyces

Cascade Kriek Brettanomyces

Cascade Kriek Brettanomyces

Cascade Kriek Brettanomyces

Cascade Kriek Brettanomyces

Cascade Kriek Brettanomyces

Cascade Kriek Brettanomyces

Cascade Kriek Brettanomyces

Cascade Kriek Brettanomyces

These organisms don’t seem to metabolize bromocresol green and stay as green colonies on BG-containing plates. That is not really a big deal since not all Brettanomyces species possess that ability anyway.

What is curious, though, is that the bromocresol green containing colonies did not remain blue, but turned green-yellow. There are about 4 other Brettanomyces strains on that same plate and they depleted the dye from the entire plate, but some of it stayed in the colonies. You can even see some blue colonies that did not turn green or white. Other than being a dye BG is also a pH indicator changing color from blue to yellow as it becomes more acidic, and as I discussed in the “Size Matters?” post, in aerobic conditions with available glucose Brettanomyces may produce acetic acid. The pKa of acetic acid is 4.76, which is exactly enough to turn BG green-yellow. This could also explain the yellow-green color of Lactobacillus colonies. The pKa of Lactic acid is 3.86, which is exactly at the border of where BG spectrum turns completely yellow. Of course right now it’s all just speculation.

Findings so far:

–       Cascade Kriek contains a lot of what seems to be Brettanomyces, which may account for the fruity character that results from fermenting with it. Not only does Brettanomyces produce fruity esters during fermentation, but it also produces fruity compounds during its acid breakdown as a survival action (see my “Size Matters?” post) and Lactobacillus provides plenty of acid.

–       This strain of Brettanomyces does not seem to metabolize bromocresol green.

–       The presumptive Lactobacillus cells are short and thick, which is a typical look of L. brevis. For example L. delbrueckii cells are longer. Sorry I don’t have my own images to show you for comparison because my entire L. delbrueckii stock died. Slightly off topic, but don’t keep your Lactobacillus and Brettanomyces cultures in the fridge. They seem to die surprisingly quickly in the cold and it’s better to keep them warmer and passage once in a while. But that’s for another post. Here is a nice collection of pseudocolored SEMs that you could look at for comparison, just keep in mind the scale differences (L. delbrueckii is a subspecies of L. bulgaricus.)

–       These bacteria are aerobic (another L. brevis trait) and grow much better in aerobic conditions.

–       Both organisms seem to produce acid in aerobic conditions with glucose as the carbon source.

Future directions

–       First and foremost I’ll try to test the hop resistance of these bacilli and, hopefully, confirm their beer souring ability. There seemed to be a chance to do genetic testing of that trait for a while, but I don’t think it’ll play out in the end and it’ll have to be done by a stepwise increase of IBUs in the growing medium. Luckily I saved a few hundred mL of a 120 IBU IIPA back when I brewed it and it’s been frozen for a few weeks just for that purpose.

–       Irregular shape of the presumptive Lactobacillus colonies suggests motility (ability to move), which is a trait that L. brevis is supposed to possess. For example Lactobacillus delbrueckii that is readily available from WYeast or White Labs is non-motile and forms round colonies. Just to be sure I’ll make some motility agar tubes next time I pour plates and stab them.

–       Gram stains to confirm that they are gram-positive.

–       What’s a little troubling is that these bacteria do not seem to produce acid when given lactose as the sole carbon source. Both presumptive Brettanomyces and Lactobacillus grow very happily on lactose, though not as quickly as on glucose, but do not produce any acid. Perhaps anaerobic conditions are required and I’ve already put them into an anaerobic chamber to see what happens.

–       The seeming acid production from glucose seems intriguing and will have to be done in liquid cultures with proper pH measurements and indicators.

Sounds exciting, doesn’t it? I’m curious to see what results will turn up from this little study.

The Kriek culture is just one of the few that you guys sent me to analyze and each one deserves attention and work. Sounds like a busy year already! Thanks again to all my readers for your support, collaborations and yeast trades and I wish you well. Some of you, however, didn’t send the cultures that you promised or stiffed me on the shipment costs, and for that may your beers be infected and not in a good way!

Happy Holidays!