homebrewer

Reducing Oxygen in Your Finished Beer

Good To Know
This week I look at methods to reduce oxygen in your finished beer. Oxygen is known to negatively impact beer flavor and long term stability. While oxygen is widely used at the beginning of fermentation to aid in yeast growth, the yeast effectively scrubs virtually all of the oxygen out of the beer during fermentation. […]
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Let’s Talk About Blending Sour Beers: Growth Rings 2023

Good To Know

This is the second in a series of posts each covering an aspect of brewing mixed-fermentation barrel-aged beers where my opinions have changed significantly since I wrote American Sour Beers 10 years ago. Each post will focus on our process, recipe, and results for one of the beers in the Sapwood Cellars Shipping Club (includes 6 bottles, for $146, cancel anytime) - sign-ups for the first box close May 5th! This post covers blending through the lens of Growth Rings 2023 (our blend of 1-, 2-, and 3-year barrel-aged sours). If you are closer to the brewery, May 10th and 11th I'll be doing a talk and vintage sour tasting including pours of Growth Rings 2021 and 2023!

As a homebrewer, my experience with blending was limited to a handful of batches. Over the last six years I've had a hand in blending more than 70 batches of barrel-aged sour beer. So, I thought it would be valuable to give my thoughts on the process, what I've learned to do, and not to do.


Setting Yourself Up For Success

You can't blend great beer if you don't have options. Creating variety starts on brew day and continues through fermentation and aging.

Malt Bills - More so for darker sours, it's good to have options for beers that have different flavors to pull from. Even for pale beers, having different grains (wheat, oats, rye, spelt, light caramel malt etc.), and starting gravities can be valuable for creating range. 

Hopping Rates - As I discussed in my previous post, hopping rate plays a large role in acidity and "funky" aromatics. Bitterness itself can be a valuable flavor in a blend, it's a flavor present in most lambics, and too often missing from American sours. 

Acidity - Having "Brett only" barrels is a good way to ensure you have beer available that won't be too acidic. When a barrel starts getting too sour, we'll often keg it so it is available for blending at a low level for beers that aren't sour enough.

Barrels - A blend of "new" and well-used barrels. Early on all of our barrels were first-use (to us). As a result many of our early releases were too woody, giving "lumber aisle" vibes. Most sour beers are light and delicate and too much oak can overwhelm. At the same time, it's good to retire barrels that aren't producing spectacular beer allowing you to bring in new characterful barrels (we currently have fresh gin, Madeira, PX Sherry etc. aging). If I was starting a new barrel program, I'd soak half of the barrels slated for pale beers with multiple changes of hot water to leach out oak flavor and tannins before filling.

Microbes - It is easiest if you have the same culture in all of the beers/barrels. In that case you don't have to worry about additional attenuation after packaging. For me, it's more valuable to have a variety of microbes for different acid levels and Brett profiles for more dynamic flavor options. As time has gone on we've split the difference, pumping in some of a favorite barrel to a fresh batch, but then going into various barrels with their own cultures. We'll also pitch additional microbes if a barrel isn't headed in a good direction at 6-12 months. 

Ages - It can be helpful to have the same/similar beers of various ages so you can balance flavors. We've gotten better at judging which barrels just need more time, and which are headed in a bad direction and need to be dumped. That said, I don't have as much time to taste/monitor the barrels as I should and I still "miss" some good barrels leaving them in too long until they taste oxidized or off. 

The Mechanics of Blending

Think about the goals before you start. What is the concept? What other ingredients are you adding after blending? What is the target volume? Sometimes it is good to just taste barrels for inspiration, but that can be overwhelming when you have dozens of barrels to select from. I try to set a general schedule before the year starts. It keeps me on track for seasonal ingredients, sourcing barrels for finishing, and utilizing our staff/tank time rather than bunching up releases. I tend to earmark barrels as "potential" candidates for a blend, ideally twice as many barrels as a blend would require. 

From there, I go to our barrel-spreadsheet (more info). I filter for beers with enough age, appropriate bases, removing barrels that are already earmarked for other projects. Lots of releases overlap, say I fill five barrels with sour red and hope to get a two-barrel blend plain and a two-barrel blend with fruit. Hopefully I have an "orphan" barrel that was passed over from last year or another similar base that didn't fit in its blend available for variety. Then I start pulling nails and tasting to gauge my options. I note barrels that need more time and those that are running out of time. Hopefully that narrows down my choices to five barrels at most for a two or three barrel blend. 

Then I pull larger samples of those barrels so I have enough beer for a few blends without having to go back and pull more. When possible, I try to create full-barrel blends, although we occasionally keg-off partial barrels for future blending stock. In the same way if a blend is missing a little something, I'll take a look through our kegs and see if there is an option that satisfies the need. 

I usually break down my options by acidity. If two barrels are a bit too acidic and two are not acidic enough, I'll try blending my favorite from each camp together to see where that gets me. Then swap in the other if there is something that doesn't work. Once I get a solid blend, I might go hunting for a little something extra. For example we were just blending a sour red, and ended up with a little 3+ year-aged Vin de Cereale (strong sour red) as a low-percentage malt-booster bringing perceived sweetness and more oak. 

In terms of the practicalities of blending, I usually use volume. Weight works, but I tend not to worry about extreme precision because the volume in each barrel can differ by 5-10% anyway. For each blend I start with an empty cup to avoid issues with tracking when you take a sip, dose in more and then don't really know the ratio. 

Finally, I write down the winning blend. When possible, I come back and taste the blend on a fresh palate later, ideally with someone who wasn't involved in the initial blend (since that is how the majority of people drinking the beer will approach it). 


Blending takes time and practice, but one thing that has been immensely helpful is blending with other people. Some of my favorite collabs are sensory rather than recipe-based. There isn't often much I get out of brewing a collab beer, instead we invite in other brewers to taste through our barrels and help select a blend, brainstorm adjuncts etc. Sam, Tim, and co. from Other Half helped blend Throwing Hearts. Jennings from Pen Druid came in to blend Life is Ridiculous. Mike Thorpe from Afterthought visited last week to blend an upcoming beer with hardy kiwi and New Zealand hops. We've done similar things on the stout side with Mike Saboe from Toppling Goliath and Eric Padilla from More/Open Outcry. Heck it's just great bringing in homebrew friends with good palates to help taste barrels, bounce ideas off... and just give me an excuse to pull samples!

Recipe: Growth Rings 2023 

Barrel #16 

Beer: Golden Sour (Pils, 2-row, Chit, Wheat Malt, .5 lbs/bbl Aged Hops, 1.056)

Age: 16 Months

Barrel: 5th-fill Pinot Noir American Oak 

Culture East Coast Yeast Flemish Ale

Notes: Rubbery funk, medium acid, bright, good

Barrel #19 

Beer: Rings of Light (2-row, Chit, Malted Wheat, Unmalted Oats, 40 IBUs in Whirlpool, 1.062)

Age: 8 months

Barrel: 4th-fill Chardonnay American Oak. 

Culture: Omega Brett C and Yeast Bay Amalgamation

Notes: Less acidic, funky, bright fruit, rubbery

Barrel #20 

Beer: Marylandbic (Pils, Unmalted Wheat, Chit, .5 lbs/bbl 2014 Celeia pellets, 1.045)

Age: 35 months. 

Barrel: 2nd-fill Chardonnay American Oak. 

Culture: Omega Brett C and Yeast Bay Amalgamation (plus a house culture that was a repitch of a repitch in primary)

Notes: Loamy, a touch stale, bright lactic acid.

Barrel #62 

Beer: Belgian Pale (Pilsner, Wheat Malt, Vienna, 15 IBUs Sterling First Wort, 1.048)

Age: 27 months

Barrel: 2nd-fill Cabernet Franc French Oak

Culture: SARA Saison Bernice

Notes: Sprite, tart, but not highly acidic.

Growth Rings is the rare bottle-conditioned sour that we didn't repitch with wine yeast, a good choice if you're looking to harvest bottle dregs!

Tasting Notes: Growth Rings 2023

(My personal notes from a few months ago)

Smell - Citrusy nose, apricot, hay, bright and fresh. Missing that big rubber that is present in most great lambics. 

Appearance - Pale gold, clear, lots of bubbles, thick head, good retention. Great lacing.

Taste - Delicate acidity. Lemon, apricot, just a touch of rubber. 

Mouthfeel - Snappy carbonation, medium-light body. Lighter bodied than a classic Gueuze. 

Drinkability - In terms of drinkability, it’s my favorite recently. Lively, complex… but it isn't as gueuze-y. 

Changes for Next Time - It has sort of a barrel-aged saison quality more than gueuze. Maybe that fresher whirlpool hop character from Rings of Light… that said I really like the result. 

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Did I Wreck Sour Beer in America

Good To Know

My book, American Sour Beers, is turning ten next month! I wrote it from the perspective (and experience) of a homebrewer. I wanted to experiment and learn. I really didn't know much about brewing commercially, creating consistent blends, adapting recipes as a barrel program matured, developing flavors that would sell etc. Looking back I have to ask, did my book help launch 1,000 barrel programs, without providing the knowledge brewers actually needed to succeed?


Over the last decade American craft brewing had an explosion of breweries ramping up barrel-aged sour production, followed by a pretty rapid decline (including multiple mid-sized breweries closing their programs and sour-focused breweries closing). Part of that is the inherently less-predictable nature of mixed-fermentation (when you order a cherry sour beer, what are you expecting? Kriek, cherry juice, cherry vinegar etc.). Compare that to a bourbon-barrel vanilla-bean stout where you have a pretty good idea of what the intent was. I suspect at least part of it was the oversaturation of the market combined with the high prices.

Despite brewing my first sour beer in 2006, becoming a brewery consultant in 2011, writing a book in 2014, and opening a brewery in 2018... I haven't been consistently happy with the barrel-aged mixed-fermentations I made until the last couple years. I certainly never released a beer that I thought was bad, but there were certainly had batches that were too sour, muddled, under/over carbonated, or just didn't "pop." During that time we've also released some amazing beers that I still love!

At Sapwood Cellars we've relied on our local club members, and the people who walk in the door to buy ~10,000 bottles of barrel-aged sour beer a year. That may sound like a lot, but it's less than 5% of our production (and we're a pretty small brewery). There really hasn't been much interest in barrel-aged sour bottles in our limited distribution range. They tend to be beers that sell best when you can explain them directly to the drinker, rather than just have them sitting on a shelf! If only there was a way I could talk directly to beer drinkers interested in sour beer...


Rather than bury the lead more than I already have, Sapwood Cellars barrel-aged mixed-fermentation sours are now available for shipping within much of America through a Membership Club administered by Tavour! Shipping is available to: WA, CA, OR, NM, NV, CO, MN, NY, DC, CT, NE, MA, FL, PA, NH, NJ, ID, TX, KS, IN, WI, MO, IA, IL, MI, ND, VA, RI, NC, SC, and MD.

The first installment of the club is $146 (including shipping) for one 500 mL bottle each of six beers: 

Growth Rings 2023: Three-year-blend of barrel-aged Sours, essentially our cuvee of bases, barrels, and microbes showing off our house character. This one isn't refermented with wine yeast, so the dregs would be a good option if you are looking for microbes! It was the second highest-rated "Gueuze" on Untappd in 2023!


Barrels of Rings: Our pale ale base, mixed-fermented in wine barrels and then dry hopped right before bottling. Citrusy-funky with restrained acidity.


Jammiest Bit: Our homage to Hommage, a barrel-aged sour on loads of sour pie cherries and red raspberries. Fruity, funky, tart etc.


Botanicia: A blend of pale sours aged in gin barrels that we then infused with dried limes and quinine. A weird play on a gin-and-tonic... but with a lot more acidity and funk!


Elliptical Orbit 2023: A continuation of the "Dark Funky Saison" series still with my original collaborator and homebrew buddy Alex. For this one he roasted Geisha coffee beans and we infused the barrel-aged dark sour with Geisha cascara (dried coffee cherries). 


Fruit of Many Uses: We sequentially racked the same barrel-aged tart/funky base onto second-use Chardonnay wine grapes, cherries, raspberries, and white nectarines. All of the fruit was whole/local.


Over the next couple weeks I'll be posting my detailed tasting notes on each of the beers, along with recipes, lessons learned, and suggestions for brewing something similar at home! I'll repeat for each club release, assuming enough people sign-up for the club to make it viable. 

Over the last five years it isn't "one simple trick" we learned that improved our beer. It's the accumulation of 100 little things from ingredient selection, to blending, to process refinement, to equipment that we've figured out. It's sitting down with each beer, drinking, thinking, taking detailed notes, and iterating. So much of it is not doing it by myself, having Scott, Ken, and Spencer to push to do things I wouldn't have (Botanica was Ken's baby, and Barrels of Rings was Scott's). Both are delicious, and they are certainly beers I would not have brewed if it was all up to me!




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STORIES FROM HOMEBREW CON 2022! | Free Beer Friday

Beer Kit
This month, we’re giving away a year’s supply of Viking Malt! Enter for your chance to win here: https://www.morebeer.com/content/FreeBeerFriday We’re giving away Nate’s Citrus Bomb beer kits this week! Fill out our weekly survey to enter to win here: https://www.morebeer.com/content/FreeBeerFriday Subscribe to MoreBeer! on YouTube – https://www.youtube.com/channel/UCv58v5jA_N-kdVMpLB-yL5w?sub_confirmation=1 0:00 Intro 0:11 Recapping Homebrew Con 2022 5:22
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Are Thiols a Scam? Thiolized Yeast, Phantasm, and the Rise of Designer Beer

Good To Know
Thiols are the coolest thing in brewing hoppy beers since the invention of dry hopping. It seems like almost every collab Sapwood Cellars has been invited to brew over the last 18 months ends up "Thiolized": 3S4MP (Cosmic Punch IPA with Phantasm and Nelson Sauvin at Fidens), Cone Concentrate (Cosmic Punch DIPA with Simcoe at Other Half DC), Celestial Paradox (London Tropics IPA with Strata/Galaxy/Citra/Simcoe at Toppling Goliath), Yasokeee (Helio Gazer DIPA with Peacherine, Hydra, and Phantasm at Cushwa), and most recently Heisenberg (Helio Gazer DIPA with Galaxy/Nelson at Commonwealth).

So why all of the excitement from our fellow craft brewers? Obviously many of the collab requests are due to Scott's writing about and advocacy for thiols, but are they just something new that will be passé soon, or are these strains here to stay?


What Are Thiols?

Thiols are sulfur-containing compounds that are often potent aromatics. The ones brewers are excited about are tropical, winey, and citrusy, while other thiols are intensely unpleasant with aromas of garlic or rotten eggs... which is why the thiol mercaptan is added to natural gas to alert people to leaks. The "skunky" aroma of light-struck beer is also 3-methyl-2-butene-1-thiol.


Unlike many other beer aromatics that require concentrations in the ppm (parts per million) or ppb (parts per billion) many thiols have an aroma threshold in the range of 5-70 ppt (parts per trillion). This means that it doesn't take much of them to be apparent, but also means that it doesn't require "high" concentrations to become dominant. 


In terms of positive beer and wine aromatics, the thiols that get the most attention are 4MMP, 3MH, 3MHA, and 3S4MP. These have perceptions that range from passionfruit, to grapefruit, to rhubarb. These are the intense aromatics that give New Zealand Sauvignon Blanc wines their distinct aromas and are found free at low-levels in many New Zealand hops (as well as some other varieties from around the world).


Most of the thiols found in hops, malt, and other botanicals are bound and thus not active aromatically. Enzymes are required to free them. There are wine strains available capable of this, but getting those genes into brewer's yeast requires more work. 



Where Do Thiols Come From?

Bound thiols are found in both malt and hops, but levels vary widely. The bond in need of breaking comes in two "flavors" Cysteinylated (Cys) and Glutathionylated (Glu). The vast majority (90%+) in both malt and hops is Glu. The IRC7 gene in certain wine strains and Omega's Cosmic Punch can only work on the less common Cys. As a result, mash hops are most potentially beneficial for Cosmic Punch, as the enzymes in the mash (especially in the acid-protein rest temperature range) can help convert Glu to Cys. Luckily some less expensive hop varieties have the highest levels of bound thiols. We've used Saaz, Cascade, and Calypso with good results.


The more intense strains like Berkeley Yeast Tropics line and Omega's Helio Gazer, Star Party, and Lunar Crush can simply be added to a standard recipe with or without whirlpool hops. Rather than having more copies of the IRC7 gene, they have a wholly different gene which can free Glu-thiols directly. The IRC7 gene in Cosmic Punch is "sourced" from yeast, while patB Omega uses in the more assertive strains is from a bacteria (if transgenic CRISPR/Cas9 gene modification is a step too far for you). We fermented a kettle sour which only had a small dose of hexalone (isomerized hop extract for head retention) with London Tropics. The result was intensely passion-fruity, so much so that it could almost pass a fruit beer. 


GM (genetically modified) yeast strains aren't allowed in commercial beers in many countries (e.g., Canada, New Zealand). As a result there are labs working with wild isolates capable of freeing thiols for co-fermentations (e.g., CHR Hansen - it is primarily marketed for NA beers) and breeding strains with heightened thiol freeing capabilities (e.g., Escarpment). Omega initially worked on yeast breeding between English ale and a wine strain capable of freeing thiols... our trials with it (Designer Baby) were interesting, but had too much of the wine strain's idiosyncrasies present (poor flocculation especially). 



Pros & Cons of Thiol-Expressing Yeast

Pros:
-Intense aromatics that are otherwise impossible to achieve from hops, malt, and yeast
-Thiols have incredibly low aroma thresholds... measured in ppt (parts per trillion)
-Thiols are "free" no expensive hops or fruit required
-Thiols may help increase shelf-life by scavenging oxygen

Cons:
-Higher perceived "sulfur" aromatics are frequent in thiol-freeing strains
-Some brewers/consumers/countries prefer to avoid GM ingredients
-Thiols can be "one note"... is it really that different from adding a jar of passion fruit extract?
-Repitching the yeast doesn't make as much sense if you also want to brew English Ales, Porters/Stouts etc. 



More isn't (always) Better

Initially there was a focus on maximizing thiol concentration. This could include colder fermentation temperatures, mash hops, and engineering strains with more assertive genes. Like most aspects of brewing (or cooking) maximizing a single flavor compound doesn't usually result in the best overall flavor or balance. 


Thiols aren't typically a "primary" aromatic in beer, so a beer with over-the-top thiol concentration without anything to play off of can taste artificial. On the other hand, some of our heavily dry hopped DIPAs have tested at over 100X the flavor threshold for 3MH and still weren't the primary aroma thanks to competition from the "traditional" hop aromatics. From those test, I wouldn't worry about dry hopping removing all of the thiols.


As a general rule, I'd suggest using a more restrained approach to thiols in lighter/cleaner/simpler beers. It doesn't take much to add a unique twist to a lager or American wheat, where a double-dry-hopped DIPA or fruit beer may benefit from a much higher amount. In the end it's about your palate and goals for a beer. 


In my experience expressing thiols doesn't make every hoppy beer better. They add a distinct note that can greatly enhance the perception of passionfruit-type aromatics. That is a wonderful contribution when you are leaning into those flavors, but can be distracting or muddle other flavors. For example, I love the "mango popsicle" aroma of great Simcoe. However, with one of the intense strains like London Tropics or Helio Gazer in an all-Simcoe beer can become more generically "tropical" rather than varietal "mango." On the other hand, when dry hopping with passion-fruity Galaxy, or brewing with actual passionfruit the thiol note helps to enhance the existing aromatics. 



Phantasm

Hand-in-hand with thiol-expressing yeast goes Phantasm. It is essentially the dried and powdered remnants of the highest-thiol New Zealand Sauvignon Blanc grapes. As a result it comes with a high price-tag of ~$35/lb. It really doesn't smell like much before fermentation. Added to the whirlpool it adds a huge amount of bound thiols for the yeast to work on. 


During fermentation I detect a distinct "white grape" flavor and aroma that I don't get from other thiol-expressing ferments that rely on grain and hops alone for bound precursors. A lot of this drops out with the yeast however and the finished beers are rarely as distinct. To my palate the added expense is hard to justify in a highly-dry-hopped beer where the thiols are competing against other big aromatics. Unless you lean into those aromatics with a hop like Nelson Sauvin. I like Phantasm best when it is paired with actual white wine grapes, or in a simple base where it can star. 


We haven't used Berkely Yeast's "Thiol Boost" additive yet... but I'm just not that excited about a 15X increase on the already intense London Tropics level of 3MH. I'd be interested in herbs or additives that could push other unique thiol aromatics that we aren't getting from grain/hops. 



My Favorite Thiolized Batches

At Sapwood Cellars, we've brewed a few dozen batches between Cosmic Punch, London Tropics, Lunar Crush, and experimental isolates. I've enjoyed most of them, but a handful stand-out as beers I loved!


Cosmic Rings: Galaxy and Citra is one of our favorite combinations... but we have had a difficult time sourcing great Galaxy (that doesn't taste like honey roasted peanuts). This all-Citra double-dry-hopped pale ale starts with New Zealand Taiheke (Cascade) in the mash and kettle. It's one of our favorite whirlpool hops because it is low alpha acid and has a beautiful tropical aroma... not to mention a lower price compared to other New Zealand varieties like Nelson Sauvin and Riwaka. Then we ferment with Omega's Cosmic Punch which brings some tropical aromatics without becoming distracting or artificial. Finally we dry hop with Citra and Citra Cryo at a combined 3 lbs/bbl.


Tropical Pop: Kettle sour fermented with Berkeley Yeast London Tropics along with passion fruit and mango purees. Passion fruit is expensive, fermenting with London Tropics boosted the passion fruit aroma allowing us to use less without sacrificing the aroma intensity.


Field Learning: As a homebrewer I loved being able to dump a bottle of thiol-rich New Zealand Sauvignon Blanc into a keg of mixed-ferm saison. That wouldn't be legal commercially, but what we did for this collab with Bissell Brothers was to brew a restrained base with Hallertau Blanc in the mash and Phantasm in the whirlpool and age it in fresh Sauvignon Blanc barrels along with Bissell's house culture. After a year we added fresh Chardonnay grapes from Crow Vineyards here in Maryland. The tropical notes from the thiols survived barrel aging and gave the beer depth we wouldn't have gotten from grapes and barrel alone.



Takeaways

Are thiols a scam? No, but they also aren't an innovation that fundamentally changes what it takes to make a delicious beer. Consider a thiol-freeing yeast when additional passionfruit-type aromatics will enhance your beer. Don't worry about maximizing the thiols unless you they will be competing against other strong aromatics. 


I suspect that this is just the lead in to even more exotic genetically modified yeast strains (we have a pitch of Berkeley's Sunburst Chico which is modified to express high levels of pineapple-y ethyl butyrate). If you can produce a flavor compound without the cost, environmental impact, variability of growing it I suspect the economic pressures will be too great! That said, making delicious beers isn't about maximizing one or two compounds (in the same way that vanilla flavoring is inexpensive, but doesn't fully replace the depth and complexity of real vanilla beans). 




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Small Craft Brewery Yeast Management

Good To Know

When it comes to brewing delicious beer, there are few aspects more important than the yeast. A healthy fermentation allows the malt, hops, and adjuncts to shine. Pitching the right amount of healthy cells helps ensure that the finished beer has the intended alcohol, expected residual sweetness, and appropriate yeast character.  

Over the last four years at Sapwood Cellars we've slowly improved our yeast handling. We've noticed improved fermentation consistency, and better tasting beers. Most of our process is excessive for a homebrewer, but it might give you some ideas!

Harvesting Yeast

We harvest yeast from moderate gravity beers when possible as these cells are less stressed and healthier as a result. Our general rhythm is to brew a pale ale with a fresh pitch, and harvest from that tank for an IPA and DIPA the following week. Once the pale ale fermentation is complete (repeated gravity readings, and no diacetyl or acetaldehyde sensory) we can and soft-crash to 56-58F (13-14C). Cold and dissolved CO2 encourage the yeast to settle out. Specific temperature and time are strain and tank dependent, but that works for most of the English-leaning strains we use (Boddington's, Conan, Whitbread, and the Thiolized-variants).

Once the beer has been cold for 24 hours, we attach a 1/2 bbl brink to the bottom of the tank and pasteurize through the line and brink with 180F (82C) water from our on-demand. 25 minutes hot ensures there aren't any stray microbes that will be passed onto the subsequent batches. After pushing out the water with CO2 pressure we spray the brink with cold water then pressurize it and the tank to ~10 PSI. 

We then dump about a gallon (4L) from the T until the yeast looks good (creamy, off-white) and then begin collecting into the brink. You don't need to dump a large volume of yeast. By keeping steady pressure on the tank and slowly releasing pressure on the brink through the valve at the top we ensure that the yeast won't come out of the cone too quickly (which could punch through pulling in more beer than yeast) and won't foam up in the brink. It takes 10-15 minutes to fill the brink. Usually we are able to collect 110-130 lbs (50-60 kg) before yeast starts coming out the top of the brink. 

We collect yeast before dry hopping to avoid having hops mixed in with the yeast. We also prefer the "less rough" flavor we achieve by dry hopping cold. If you dry hop early-mid fermentation and want to harvest, drop as much of the hops out as you can before crashing and harvesting.

Yeast Storage

Whenever possible we pitch within 72 hours of harvest. Larger yeast cultures generate more heat and thus tend to lose viability more rapidly. Store the yeast as cold as possible, which for us is ~36F (2C) in our walk-in. Ideally that would be closer to 32F (0C) to further slow its metabolism. Shake twice a day to dissipate hot-spots and vent down the pressure to knock-out CO2. If storing the yeast for more than a few days, attach a blow-off line to prevent pressure from building. 

There are studies about various additives for maintaining high yeast viability. We've added phosphate buffer to prevent a drastic pH drop. It's difficult to tell from a single data point, but viability dropped from 95% to 89% after a week of storage. We've seen closer to 10% reductions the handful of times we've stored yeast that long previously.  

We generally won't harvest and repitch beyond three generations (although recently we went to five). That's because with our limited number of tanks, variety of yeast strains, and canning schedule we'd eventually have to hold onto yeast for a couple of weeks before pitching or harvest from a strong beer. 

Determining Cell Count and Viability

There are plenty of successful brewers who pitch a standard weight by barrel/gravity, but knowing how many live cells you actually have is a great way to improve consistency. It's especially valuable if you use a variety of strains or want to bring in a new strain. Our harvests of the same strain can vary by as much as three times in terms of live cells per g of slurry (~.5-1.5 billion cells). The cost of all of the equipment required is ~$500, less than a single commercial 10 bbl yeast pitch from some labs. 

Start by shaking the brink to homogenize the culture. Then run a cup of yeast out, dump it (to avoid counting the cells packed around the port) and then pull a sample. The next step is to dilute the culture to a "workable" concentration - 1:100 for us. Too many cells packed together makes for a culture that is impossible/laborious to count, while too few raises the chances luck will throw-off the count. For a long time I diluted by volume, performing two sequential 10X dilutions with a micropipette. This had two drawbacks. First getting an accurate volume of yeast slurry is tricky because it is foamy and has small bits of trub that can plug-up the pipette. Second, we pitch by weight, so there was always some estimation when it came to converting the volume to a weight or the extra step of determining the physical density of the slurry by mixing with water in a graduated cylinder on a scale. What we do now is dilute by weight, which gives us cells per gram rather than cells per milliliter.

Our scale is accurate to .2 g, so weighing 1 g of yeast into 99 g of water has a ~20% margin of error. As a result I do 490 g of water with 5 g of the yeast slurry. This reduces the maximum margin of error to ~4%. After pouring the diluted culture back and forth to mix, I take 9.9 mL of the diluted culture with the micropipette and add .1 mL of a stock dye solution of Erythrosin B and phosphate buffer (1 g in 50mL of buffer). This results in a total dilution of 100X. You could go even further, a 10X dilution by weight (50 g yeast with 450 g of water) followed by a 10X dilution by volume (1 mL of the diluted culture with 8.9 mL water and .1 g of dye). Live cells are able to expel the Erythrosin B so they won't be stained, meaning any red yeast cells are dead. You can use a variety of other stains, but Erythrosin B is a food coloring and much safer to handle than methylene blue or trypan blue. Here's a post from Escarpmant Labs on using it inspired by my Tweet (which was in turn inspired by this).

Luckily the Boddingtons-type strain we use for most of our batches isn't "excessively" flocculent. When we fermented a run with Whitbread we ran into issues with the cells being too clumpy to count. Luckily BrewKaiser has a whole post on additions you can add to help. Phosphoric acid worked OK, but a local brewer suggested disodium EDTA, which I plan to buy before we do another run with a similar strain. 


Next, place a couple drops on the diluted culture a hemocytometer, apply the slide cover, and stick it under a microscope (we have an Omax). Count the live and dead cells in five squares (each made up of 25 small squares) - four corners, and center. This provides a large enough sample size to avoid undue randomness. A small tally counter helps keep track. The standard rule is to count cells touching the left and top lines, but not the right or bottom. Count connected cells as two only if the daughter cell is more than half the size of the mother. Then I plug the totals into Inland Island's Yeast Cell Count Calculator. Usually our harvests are 80-90% viable off a fresh pitch, and they tend to go up from there on subsequent generations (90-95%). If your viability isn't great it could either be that the yeast isn't getting enough nutrients/oxygen, your initial pitching rate was too high or low, or that you are waiting too long to harvest.  

There are automated solutions for yeast counting, but with some practice the whole processes will take less than 10 minutes.  



Pitching Yeast

To pitch, we attach the brink to a T inline during knock-out. With the brink on a scale we use CO2 to slowly push in the desired weight of yeast (calculated based on the cell count, wort gravity, and volume). We pitch during knock-out so the yeast mixes with the aerated wort as it goes into the fermentor. White Labs advocates using a pump to pitch their fresh yeast inline to achieve better mixing with the wort. Best practice is to do another cell count off the tank once knock-out is complete to validate your process (we did it a few times, but now trust our approach).

When we started brewing more double batches to fill our 20 bbl tanks, we were pitching enough cells for 20 bbls along with the first 10 bbls of wort. Our thought process was that the yeast wouldn't do much in the 3-4 hours before the second half of the wort went in. However, we found our fermentations were less reliable, often dragging towards terminal gravity, and the yeast from those batches had much lower viability than expected. Both of these issues improved significantly once we switched to pitching only enough cells for the initial knock-out volume. This allows for more growth and thus a higher proportion of younger yeast cells. 

Hopefully this overview of our process is helpful for someone starting a new craft brewery, or looking to take their yeast management to the next level. As with anything in brewing, the more variables you can track and control the more consistency you'll have in your results. Yeast management isn't a "fun" topic, but it is one of the simplest things a brewery can do to increase consistency, improve flavor, and save money!





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Pilot Project: Launching Brands and Lowering Barriers in Craft Beer

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When Bhavik Modi walked into his first ever sales meeting for his new craft beer line, he wasn’t alone. Tiffany Wooten, a veteran sales representative from brewery incubator Pilot Project Brewing, was by his side, convincing the team at high-end contemporary Indian restaurant ROOH Chicago to serve Azadi Brewing’s cardamom golden ale and Kesar mango […]

The post Pilot Project: Launching Brands and Lowering Barriers in Craft Beer appeared first on CraftBeer.com.

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Homebrewing Beer Kits

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This video covers what comes with your home beer making beer kits. It reviews the main ingredients in a homebrewing kit including the steeping or flavoring grains, dried malt extract, liquid malt extract and hops.
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5 Reasons Why Saison Is the Best Beer Style for Homebrewing

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In this video, I discuss the history of Saison and provide 5 reasons why I believe it’s the best beer style for homebrewing. Other homebrewers may or may not agree. I would love to hear your opinion. Saison Recipe Link: https://rebrand.ly/SaisonRecipe Mad Fermentationist Blog: https://www.themadfermentationist.com/ Stuff I Use (These are affiliate links. I do get
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