Are you pitching enough yeast for a healthy fermentation?

The answer depends on many variables

Most brewers recommend a pitch rate of 0.75 million Cells per milliliter per degree plato (one degree plato equals 1.004 SG) for ales and twice that for lagers. The math yields too many zeros for most calculators, so we will make this easier for you. Here is a good chart for what that means for 5 gallons of wort for ales. Double it for Lagers.



If you make 5 gallon of 1.050 SG wort, you will need around 180 billion cells of healthy viable yeast. So all you need to know is how much is in a pack of yeast, right? WYEAST, White Labs and Inland Island Fresh Liquid Packs contain around 100 Billion cells and loose viability at 20% per month. Dry packs contain 160 billion cells and loose 20% per year. Simple math says best practice means we need 2 liquid packs or one dry pack. If you choose liquid, two packs get expensive so we recommend a starter.

a White LabsWe do not recommend starters with dry yeast.

To make a starter, combine 1 cup Dry Malt Extract per liter of water with some yeast nutrient and defoamer in a glass flask.

This produces wort at about 1.040 SG. A Defoamer is highly recommended if you like your stove top clean. Boil the mixture for 10 minutes, cover with foil and let cool. Airlocks are discouraged as we are encouraging oxygen for yeast growth. After cooling pitch the yeast and allow it to multiply for 24 hours. 3 methods produce different yeast growth. Leave it alone for modest increases in cell count, shake it often for better increases cell counts, and use a magnetic stir plate for maximum cell count. There are various on-line and software estimates for cell counts, but in an example of a 1.050 wort and a 1 liter starter, we should be at about 180 billion cells in 24 hours if we shake the starter routinely to dissolve oxygen.

Under pitching or over pitching

Many have made very good beer simply by pitching the pack as is. So what is happening? When we under pitch we increase the growth phase of yeast. The growth phase is when aromatic and flavor compounds, ie esters, are produced. A longer growth phase increases yeast produced esters. We may want this with some Belgian styles but certainly not with an American IPAs or Wheat Beers. So the brewer can experiment with pitching rates to yield the flavor and aroma profile desirable.

So remember, you can make good beer with one pack of liquid yeast, but you can control flavor and likely make better beer with just 15 minutes of prep and minimum investment in equipment by adjusting your pitch rates for style and gravity.


Check out our Brew Tools page for a more geeky version of this post and use it as a reference for all your brews.Castle Rock Home Brew logo


Castle Rock Homebrew Supply has one of the largest and growing selections of beer, cheese and wine-making supplies in the Denver and Colorado Springs area. We started the businesses out of our own passion for home brewed beer and decided to teach others for to brew as well. We are proud to be able to offer a diverse ingredient list and packaging sizes that allow the beginner extract brewer to make very diverse beer. Stop by our store anytime! Or contact us online we’ll be happy to help you get a piece of equipment or answer your questions.

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