Sunday, March 3, 2013

Money For Nothing And Your Yeast For Free

Brew better beer and save money in the process by washing your own yeast for reuse in future brews. Always have a fresh supply of healthy yeast on hand and brew like the pros brew, it's a lot easier to do than you might think. The most obvious benefits of washing your own yeast are always having a good supply of viable cells on hand when needed, brewing way better tasting beer as the new yeast generations adapt to your brewing environment and saving lots of money on future yeast purchases.

On bottling day after having bottled up the very first batch of my 1960's Era Ballantine IPA recipe, one that I had spent a very considerable amount of time researching before creating the recipe and brewing it, I decided to wash the East Coast Yeast ECY10 - Old Newark Ale™ yeast that was at the bottom of the fermentor and store it for later use when making a starter to pitch into my next batch of beer. After cold crashing the washed yeast for five days at 36F the yeast cells flocculated out of suspension and formed a thick cream colored yeast cake on the bottom of the jar. Using a turkey baster I carefully sucked the top layer of the yeast cake into the baster and squirted the yeast into a dozen liquid yeast vials for storage.

East Coast Yeast ECY10 - Old Newark Ale™
 The yeast in the vials when stored at 36F in a refrigerator can retain a reasonable number of viable cells for up to 6 months or more. The yeast in the vials eventually settles out of solution and forms a thick yeast cake at the bottom of the vial, about half the amount per vial when compared to the nearly full vials White Labs ships its yeast in. When I'm ready to use my previously washed yeast I make a starter by adding two vials of  yeast to a 2000ml Erlenmeyer flask filled with a 1.040 wort and set it spinning on a stirplate. As a side note I found it to be easier to use StarSan for sanitizing the vials, caps, jars, turkey baster and anything else that may come into contact with the yeast. StarSan is fast acting and just as effective as boiling everything and it saves a lot of time besides eliminating the need to handle boiling hot jars, lids and water.
One Gallon Of Washed Yeast Slurry
I fill a tall one gallon jar up with filtered water, boil that water in a small pot it for 15 minutes then let it cool down to 72F leaving the lid on the pot. Once the water's cooled to the same temperature as the yeast cake left in the fermentor I just pour in all the water and stir it all up together by gently mixing the yeast and water with a sanitized spoon. With water and yeast all stirred up into a nice slurry together I open the spigot on the fermentor and fill the sanitized gallon jar up with the washed yeast slurry. The yeast in the slurry will slowly start to separate from the beer as the yeast cells began to settle out of solution and form a thick layer of yeast cake at the bottom of the jar.
Vials Of ECY-10 Estimated 50 Billion Cell Count Each
After tightening the lid on the jar again and spraying it with StarSan I put a sheet of plastic wrap over the top of the jar, held in place with an elastic band,  then put the jar in the refrigerator. About 5-7 days later the same milky yeast slurry becomes sparkling clear as the yeast settles out of solution and compacts at the bottom of the jar. Using a sanitized turkey baster I carefully suck up the thick yeast paste on the bottom of the jar, this is where all the healthy new yeast cells are, and fill up the vials for storage.

Excess Yeast Slurry At Left Washed Yeast Vials At Right
 I always make starters when using my washed yeast, even if the washed yeast has been stored in the refrigerator for only a week or two. Starters are all about having healthy yeast cells and then increasing the cell count. As for determining actual cell count in each vial I use an easy and reliable method, I fill up a White Labs vial with washed yeast, let it settle out and compact on the bottom of the vial and then eyeball it against what ship in a new vial of yeast. I know that White Labs ships 80-100 billion cells in their yeast vials and they contain about twice the volume of yeast stored in my vials of washed yeast that seem to contain about 50 billions cells each.

1.040 Starter Wort With Yeast Nutrient And Crumbled Hops
 I start out with 2000ml of filtered water and add to it 1.5 cups of extra light DME and mix it together thoroughly in a small pot before bringing it all to a boil for 10 minutes. I put in a small amount of pellet hop as a preservative and a pinch of yeast nutrient to help coax the yeast into producing plenty of very healthy new cells in the starter. At this point making a yeast starter is really just like brewing up a low alcohol mini batch of beer, but instead of using it to make beer it'll be used solely for the purpose of making more healthy yeast.

Cold Crashing The Boiling Wort To Pitching Temperature
Once the starter wort is the same temperature as the liquid yeast I pour two of my stored vials of yeast, each estimated to hold 50 billion healthy yeast cell,  into the Erlenmeyer flask through a stainless steel funnel. Next I pour the cooled wort through the funnel and fill the flask up to the 2000ml line and give the yeast and wort mixture a small burst of pure oxygen to get them off to a running start. The stirbar gets dropped into the flask and I spray a square piece of aluminum foil with StarSan and fold it over the top of the flask to cover the opening. Two things should be noted about covering the flask top with aluminum foil, you only want to fold it loosely over the top to allow the Co2 produced by the yeast to escape the flask and be replaced with room air. Also the bacteria and other things that are known to infect beer can not crawl, so there is a zero chance  of anything bad getting inside the flask while it's opening is covered with the foil.

Phases Of A Typical Starter Taken 12 Hours Apart
Even when boiling extra light DME to make my wort it has a darker color when it's first poured into the Erlenmeyer flask as shown in the first image on left in the picture above. But that soon will change as the sugars in the wort are consumed and processed by a rapidly growing population of yeast cells. When all the right starter conditions have been met a more than doubling the original yeast cell count can be excepted, I'd like to think my final cell counts are coming out consistently to close to 240 billions cells per starter.

When making a yeast starter it's critical to formulate, as precisely as possible, the recommended inoculation rate of viable yeast cells for 2000ml of 1.040 starter wort. I use a very simple formula where my inoculation rate starts out as close to 100 billions cells as possible and I expect that number to increase to between 220-240 billion cells once the starters finished.

Pitching Rate Calculator
 I like to pitch what some may feel is a large starter, I base my pitching rate calculations on two things the alcohol content expected once fermentation has completed and the type of yeast being used as being either an Ale or a Lager strain. My current dark ale recipe was calculated to come in 8.4% ABV and for that fermentation to go smoothly knew I needed a pitching rate of nearly 300 billion healthy viable yeast cells. I've spent the past several years fermenting my ales and lagers at their lower temperature ranges and expecting aggressive fermentations with minimal lag times. I'm on a mission to get the cleanest tastes from my malts and other additions and not have them muddied up by a bunch of yeast induced esters, unless you're into farmhouse ales and sour beers you'll probably agree with me on this one important piece of information.

Cold Crashing Starters At Day 1, Day 2 And Day 3
At the start of the new year the first recipe I brewed was my Hammerfest Marzen Lager, over the years I've brewed this style using several different ingredients and approaches to brewing, fermenting and lagering in order to find one that produced the very best tasting beer. I can't do all the brewing calculations needed on a typical brewday, or brew a recipe on paper, I rely on my brewing calculators to do most of the work for me. A medium to low gravity 5.5% ABV lager beer fermented at 52F needed a pitching rate of nearly 400 billion viable cells to ferment a five gallon batch, so I had to make two starters in parallel that week.

White Labs WLP820 - Oktoberfest/Märzen Lager Yeast™

At the end of the day all I wanted was the yeast I had no intentions of pitching a gallon of nasty tasting starter wort into my five gallon batch of beer and ruin the taste of it. Placing the starter flasks in the refrigerator at 36F for 3 days did the trick. The starters were very cloudy after coming off the stirplates but began to clear by the end of the first day and had completely cleared by the third day in the refrigerator. Pouring off, or decanting, the starter wort from the flasks and leaving just enough to swirl the yeast cake into solution from the bottom of the flasks and the yeast was now ready to pitch.

Oxygenated Wort Prior To Pitching Yeast Is The Best
Yeast nutrient has long since been included in all of my beer recipes just the way using pure oxygen and a micron diffuser to oxygenate the wort has replaced all other forms of aeration prior to pitching the yeast. During the early or aerobic phase of fermentation the yeast cells begin taking in nutrients, building strength, storing up energy reserves and reproducing at a very aggressive rate. They continue converting oxygen and nutrients into energy and reproduction until nearly all the oxygen in the fermenting beer has been depleted.

Now during the primary fermentation, or anaerobic, phase the yeast rewire their pathways and start converting the sugars in the fermenting beer into Co2 and alcohol. By reducing the length of time in the aerobic phase the excessive build up of flavor precursors are also reduced and the primary fermentation that follows can easily convert those precursors before going dormant at the end of the fermentation.

The Four Phases Of Fermentation

Phase 1 begins as soon as you pitch your yeast and is referred to as the lag phase, which we brewers want to keep as short as possible. The yeast are using up the sugars and oxygen in the wort to load up their food reserves, they won't ferment anything until they've been well fed. Stressing the yeast out with too high temperatures or too low numbers of viable cells will prolong the lag phase and the fermentation will take longer to complete while increasing the amounts and types of off flavors like diacetyl that may or may not ever condition out.

Phase 2 starts as soon as the lag phase ends because now the yeast have enough energy stored up to start multiplying, this is referred to as the growth phase. This is where you begin to see a bit of foam floating at the surface the wort from the production of Co2 and the pH and oxygen levels of the wort will start dropping. If you've pitched enough healthy yeast at the right temperatures into well aerated wort the lag time should have been 6-12 hours and the yeast are now full of energy and off to a very healthy start.

Phase 3 begins as soon as the growth phase is done and is triggered by a lack of oxygen in the wort, this is known as the fermentation phase. This is the phase where the production of Co2, alcohol and your beer's flavor is at it's peak and the wort temperature rises 3-5F higher than the ambient air outside the fermentor. The yeast will stay in suspension, so they come in contact with as many sugars as possible, over the next 3-7 days before they run out of sugars to eat and flocculate out to the bottom of the fermentor. Higher temperatures during this phase will produce more esters or fruity flavors and aromas, like the banana flavors in a hefeweizen. It's interesting to note that another cause of ester production is wort that hasn't been aerated enough.

Phase 4 is the final phase of the fermentation process and it's referred to as the sedimentation phase where the yeast begin consuming and converting any remaining flavor precursors in the wort like diacetyl that will produce off flavors in your beer. During this phase the yeast cells are preparing themselves to go dormant and storing up energy reserves for their deep sleep, even though this is where most of us flush them down the drain. I'd like to point out that the amount of cleanup work left for the yeast to do is dependent on how well we treated, or mistreated, our yeast during the first 3 fermentation phases.

During the sedimentation phase I raise the temperature of my fermentors 3-5F and hold it there for at least 3 days before bottling or kegging my beer. I do this because the yeast will only convert the flavor precursors they created earlier if the beer is warmer than it was when they were created. There is a limit to this rule though since the yeast can only do so much cleanup before they go dormant. Once the yeast go dormant any remaining flavor precursors will be left in your beer to produce off flavors.

Screwy's Golden Age IPA
For you history buffs out there Ballantine IPA was once the largest most popular selling beer in America beating out another upstart of that time named Budweiser. At the height of their fame Ballantine owned their own grain warehouse, malting house and even had their own hop oil extraction process which they used in abundance in their beers of the day. The original 1960's era Ballantine IPA was recorded as having been a 7.5% ABV 60 IBU aged in wood for up to a year before bottling. I've researched the historical records for this original recipe and managed to create an all grain version I call 'Screwy's Golden Age IPA' fermented with East Coast Yeast ECY10 - Old Newark Ale™ yeast, the original strain of yeast used back then in the Newark NJ brewery.


  1. Great post on managing yeast for homebrewing. If I were to start all over again, I would work hard to get my yeast management process down before I focused on anything else - well, maybe except for cleaning and sanitizing.

  2. I agree it's amazing how much better your beer ferments and how much money a brewer saves when propagating and pitching their own yeast. But fortunately each year new brewers are becoming more aware of the importance of not only quality recipe ingredients but the benefits of good yeast management as well.

  3. This is something I have never done. I only brewed Mr Beer for a long time until they were bought out. Once that happened I did not brew again for a year or so. Now days I am doing extracts with grains and here soon going all grain.

    In your opinion, it is worth while to wash dry yeast after it has been used or is this something you would only do to liquid yeast strains? And I have saw many build home made stir plates. is this worth the effort or just as easy to buy a stir plate and stir bar?

    1. Even dry yeast, that has been washed after fermentation, is a good candidate for storing and reuse. Of course there's no need to make a yeast starter from dry yeast, nor is it recommended, but that's really where differences between liquid yeast and dry yeast end.

      Since building my first stirplate some years ago, which I still use on occasion, I have bought two stirplates that I use too. If you enjoy tinkering then building your own brewing gear can be a lot of fun too.