How to make a yeast starter for beer

by Daniel on February 7, 2012

Yeast starter for beer

My 3 quart yeast starter split amongst 2 growlers

Since I decided to make a yeast starter for the first time for my most recent Belgian tripel, I thought I would add my experience to help others with when, why, and how to do it.  First off – don’t be intimidated.  There are many different ways to make a yeast starter for beer, some can be complicated & involved with extra equipment.  Fear not, you can make a perfectly good starter with exactly what you have.  Second – you don’t have to do this for most beers you are going to brew.  Most often you will be fine buying a WYEAST smack pack with 100 billion cells.  I’m sure I could be criticized by many aficionados for saying such, but  for simplicity’s sake and the length of a blog post, let’s go with it.

WHEN:  To simplify, if you’re planning a beer that has an original gravity of 1.065 or less (many, many beers), you’re fine with a smack pack.  If after this post you still don’t want to do a starter, you can always add two packs.  So if you’re making a strong beer, like a Belgian tripel for example (my OG was 1.085), you want to start out with more yeast cells.  Another time you need to pitch more yeast is for cooler fermentation temperatures (lagers, etc).  I’m going to be talking about ale recommendations, because I haven’t gotten into lagers myself…I’ll get there eventually.

WHY:  If you start with too little yeast for your big beer, the yeast you pitch will spend much of their time reproducing to reach the maximum population that can be supported by the wort.  Yeast reproduction results in production of by-products that can lead to off-flavors.  Some of these can be eliminated by bottle conditioning, but many can’t.  So if you want to really have control over the final flavor of your beer, and be able to reproduce it, you want to make sure you pitch enough yeast.

HOW:  Easy – you make a mini wort, cool, and pitch your yeast into it.  Equipment: Yeast to be pitched, pot for your mini-boil, malt (best to use the same extract that will be in your beer), fermentation receptacle such as a mason jar, mayonnaise jar, or growler (I like the latter). Pros use an erlenmeyer flask and a stir plate to keep things aerated yada yada.  You’ll be fine without the stir plate or the erlenmeyer, trust me.  My starter for my 1.085 Belgian tripel started bubbling less than 6 hrs after pitching.  If there weren’t enough yeast cells to start, the lag time would be a lot longer while the yeast were building up numbers (this is what happened the first time I made this beer, which is why I looked into making a starter).  Since a lot of us home brewers have a growler from another place lying around, that’s what I recommend.  To make a 1.040 OG starter (your starter doesn’t have to have the OG of your upcoming batch), the general rule is 2 cups water per 1/2 cup dry malt extract.  I’ll refer you to pages 68 & 69 of John Palmer’s How To Brew book for ratios of recommended pitching rate by OG, and final yeast count per quart of this starter.  Anyway, starting with my 100 billion WYEAST pack for a 1.080 estimated OG, and a desired final yeast count of 270 billion cells, I made a 3 quart starter.  So here’s the simple steps, and yes, you can really just do this and you’re in good shape:

  1. How to make a yeast starter for home brewing

    Boiling the wort for 10 mins

    Make your starter 3 days ahead of brew day

  2. Calculate how much volume of wort you need based on the goal cell count for your estimated OG (see How to Brew)
  3. Sanitize your growler or other container
  4. 2 cups water per 1/2 cup DME
  5. Boil water, turn off heat, add your DME, and bring back to boil for 10 mins (really 10 is fine)
  6. Cool to pitching temp (the same temp you want to pitch your yeast to on your full bacth – this is important)
  7. Put wort into your sanitized container & pitch your yeast
  8. First, cover with your sanitized growler cap and shake vigorously to aerate, then remove cap
  9. Sanitized tinfoil wrapped over the mouth/opening is sufficient to keep bugs out while letting out CO2.  You can do an airlock if you want.
  10. Maintain fermentation temp (see my fermentation chamber/heater build) – constant temp really makes a difference
  11. The night before brew day, put the starter in the fridge.  This will settle the yeast to the bottom and allow you to pour off all of the used wort (you don’t want it to affect the flavor of your beer), leaving the yeast to pitch directly into your beer.  It’s okay, even beneficial, to pitch it cold right from the fridge.  The cold also get the yeast in “hibernate mode” so they build up resources that are useful for them to get a fantastic start as soon as you pitch to your perfectly-temperatured full batch wort.

Happy brewing!

{ 2 comments… read them below or add one }

RGV Realty February 12, 2012 at 11:54 am

great post! Keep up the excellent work!

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Dr. D February 9, 2012 at 6:23 pm

Thanks for a great time last weekend learning how to brew beer. I definitely enjoyed learning the technical aspects of brewing. Your instruction were very informative. That last Tripel you brewed was incredible! Looking forward to tasting this next batch.

Cheers

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