Build an Army of Yeast-ies

Author’s Note: Post contains affiliate links.

IMG_5581The old saying holds true, “Brewers make wort, and yeast makes beer.”  Yeast gives our brews their alcohol content (hooray!), and many yeast strains add distinctive flavors.  It’s no secret that growing, harvesting, and saving yeast is one of the biggest cost savers in home brewing.  With White Labs vials going for $7-$11 and Wyeast Smack Packs going for $8-$14, yeast can easily become one of the biggest ingredient costs.  Higher gravity beers (1.060+ Original Gravity) will even require multiple vials/smack packs to achieve the correct pitch rate, taking your yeast cost to $14-$28 per 5 gallons!  Fortunately, you can virtually eliminate this cost by taking a few simple steps…

Many brewers start with dry yeast for the relatively low cost and simplicity.  You buy a pack, cut it open, and sprinkle into your fermenter… done and done.  However, dry yeast can limit your beers’ potential to achieve more interesting and diverse flavor profiles.  I highly advocate making the switch to liquid yeast.  It requires a bit more effort and planning, but the results are well worth it!

The steps I list out below are not necessarily a sequential process.  Try any that you like, as they will all result in serious money savings long term.

Step 1: Make a Yeast Starter – savings = $7-$14 per 5 gallons

I ignored this piece of advice for a long time.  I just assumed that the lab techs at White Labs were smart enough to make yeast vials that could ferment any beer in any quantity at any gravity.  After one of my higher gravity fermentations (1.069 OG) got stuck, I did some research.  White Labs vials and Wyeast smack packs are designed to pitch the appropriate amount of yeast cells into 5 gallons of wort with OG of 1.060 or less.  Higher gravity beers will require a higher pitch rate, or the yeast can become stressed and produce off flavors or miss the target final gravity.

Yeast CalculatorUnless you want to buy and pitch multiple vials ($$), a yeast starter will solve your problems.  Starters serve the purpose of growing your yeast cells to the appropriate quantity, increasing yeast health, and stimulating yeast activity.  Starters are extremely simple to make, and I recommend using the Brewer’s Friend Calculator to determine the pitch rate and starter size you will need.  Once you know your starter size, you will need to create some wort with OG of approximately 1.040.  Simply mix Dry Malt Extract (DME) with water at a ratio of 1g per 10ml to achieve this gravity.  For example, a 2L starter should contain 200g (7oz) of DME.  You can use the calculator above to determine all of this.  I personally target a pitch rate at or above 1.00M cells/mL/degree Plato (Science, right?! – see picture).  Recommended ranges are 0.75M for ales and 1.50M for lagers.

Bring the mixture of DME & water to a boil for 2-3 minutes to sanitize, then cool it to 70 degrees F, and pour it into a sanitary container.  I use StarSan to sanitize a large glass container or Erlenmeyer flask.  Pitch your vial of yeast into the mixture and swirl it vigorously.  Cover the mouth of the container with sanitized aluminum foil and use a rubber band to hold it in place.  This will allow CO2 to escape and oxygen to enter, which is crucial to yeast growth.  Store the container at room temperature, and shake it often to keep the yeast in suspension, or use a stir plate**.  After 12-24 hours, your yeast will be ready to pitch.

**TONS of DIY stir plate tutorials available on the interwebs. I’ll add one later.

Step 2: Save Yeastsavings = $7-$28 per 5 gallons

Many brewers go through the process of yeast washing after fermentation.  This will work, but I find it to be labor-intensive and to present a high risk of contamination.  My suggestion is a quite a bit easier.  You can use this awesome calculator from HomebrewDad.  Input your specific details, and then simply add 120 in the “Overbuild Cell Count” box.  The calculator will tell you how much of your starter to split off for harvesting.  After 18-24 hours, split the starter according to the calculator (into a sterile container).  Pitch the starter into your wort, and place the harvest portion in your fridge overnight to cold crash.  Decant (pour off) the excess liquid, leaving a small amount above the yeast cake.  Swirl the mixture to get the yeast in suspension and fill a sterile 50mL tube.  Store the 50mL tube of yeast in the fridge for use in your next batch, and be sure to make a starter with it.  Rinse & repeat!CalculatorCalculator2

Step 3: Harvest Yeast From Your Favorite Beersavings = $ \infty

FullSizeRenderThis is where the real fun happens!  Imagine being able to use the same yeast as your favorite belgian quad or imperial IPA.  Until now, if you want to “clone” a beer, you have to find a similar strain of yeast available for home brewers.  Often times, the available yeast isn’t all that similar, and your beer doesn’t turn out as expected.  A prime example of this is Conan Yeast from Heady Topper, a consensus favorite among IPA lovers.  Conan yeast is key to the flavors and aromatics, with an almost “peachy citrus” character, but it is unavailable to home brewers.  So, how do we get access a proprietary, world-class strain of yeast…?  Harvest it!

Yeast growth after first step-up.
Yeast growth after first step-up.

Heady makes a particularly good candidate for harvesting, because it is unfiltered, but others will work too.  First you will need to get a can or bottle of the subject beer (multiples will work better).  Place the beer in the fridge upright until it is quite cold, which drops the yeast to the bottom of the can.  Remove it without shaking, and gently pour into a glass until only a small amount remains in the bottom of the bottle.  Prepare a small starter per the instructions above.  I recommend no more than 250mL for this starter.  Apply some StarSan to the mouth of the bottle, allow the dregs of the beer to reach room temperature, and then pitch into the starter.  Allow it to grow for 2 days, cold crash, and decant most of the liquid.  You should see a small quantity of yeast at the bottom of the container (see picture).  Prepare another starter twice as large as the first and pour it into the container.  This is called “stepping up” the starter.  Again, allow it to grow for 2 days before cold crashing and decanting.  I recommend two step-ups, particularly if you are harvesting from a single bottle.  The final step should be about 2L in volume.  Decant this starter down to around 100mL total volume and swirl the mixture.  Pour it into two sterile 50mL tubes and store in the fridge.  Once the yeast settles in the tubes, you should have around 15-35mL of concentrated yeast in each tube to use on future next brew days!

**Growth may vary, use additional tubes for storage if needed.

A Few Tips

1. Sanitation is CRUCIAL – Always, always, always take the necessary steps to ensure your environment is sanitary/sterile.  Yeast can easily become infected and all of your effort will be fruitless if this happens.  Boiling and StarSan are very important.

2. Stir Plates Help – Yeast need oxygen to grow.  More oxygen = more growth.  Using a stir plate will keep the yeast in suspension and allow for constant CO2 – Oxygen exchange.  Growth rates can be significantly higher with a stir plate.  They work best with flat-bottom Erlenmeyer flasks.

3. Use 50mL Sterile Tubes – You may notice that I do not talk about mason jars in this post like many other yeast-harvesters do.  Mason jars are very useful for harvesting, but they tend to take up a lot of space.  The also require the extra step of boiling/baking to sterilize.  I prefer the disposable, sterile tubes.  The are smaller, contain measurement markings, and are similar to White Labs vials.  This helps me know that I’m saving the right amount of yeast.

4. Control Fermentation Temps – Learn the temperature profile of your specific yeast and do your best to control the fermentation temperature within the ideal range.  You will get better fermentation results and fewer off flavors.

5. Shelf Life – Yeast will have a shelf life sitting dormant in your fridge.  I recommend using harvested or saved yeast within 6 months.  If you can’t use it in that time frame, at least make a starter with it and put it back into a new sterile tube.  This will reactivate the yeast and can prolong the life of the strain.

Yeast management is a great process to use to reduce your brewing costs and enhance your beers.  Explore the wide range of possibilities available through different yeasts.  Pick your favorites, and use the steps above to keep the strains going to save lots of money!  Grow your Army of Yeasties and send them into battle!

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4 thoughts on “Build an Army of Yeast-ies

  1. Good Post, thanks for being thorough.

    I still prefer jars however, and use plastic caps to boil rehydration water in the microwave similar to the how to on homebrewfinds.

    Boiling the lids in a pot only takes a little bit of time. I do this the day I start the starter, then once the starter is ready, the mason jar will have cooled down down. Pour the saved starter into the now cooled and sterilized jar.


  2. I’ve been overbuilding and harvesting yeast from starters for a few years now, it works incredibly well! HomebrewDad’s new calculator is super helpful for this, I’m pretty stoked he added that function. I’ve also had some success building up yeast from commercial bottles, super cool when it works out. However, there are times craft brewers ferment with one strain and bottle condition with another, meaning the yeast you prop up may not be completely similar to the one used by the brewery. Just a thought 🙂

    Great tips. Cheers!


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