This week I take a look at ways to determine how much dry yeast you need to use when brewing beer. Dry yeast pitch rates are measured in a slightly different way than liquid yeast, so understanding the yeast lab recommendations and how to apply it is an important skill to have when brewing with dry yeast.
What Makes Dry Yeast Different?
Liquid yeast is typically measured by volume and pitch rates are often determined based on the number of cells in a given yeast package or volume. You can then calculate the pitch rate based on the desired cell count. Commercial brewers often look at the millions of cells per milliliter of beer after pitching as a good measure of pitch rate, and may adjust that based on the type of yeast used and gravity of the beer. I have an article here that covers the new liquid pitch calculator in BeerSmith 4 in more detail. Also, because of the short shelf life we often will use a yeast starter to increase the number of viable cells before pitching a liquid yeast.
Dry yeast is a different beast. While most labs maintain a roughly constant number of yeast cells per milliliter for liquid yeast, the number of cells in a gram of dry yeast can vary by strain. As a result it becomes difficult to accurately calculate the number of cells in a pack of dry yeast. Also dry yeast has a long shelf life if properly stored, so you rarely need a dry yeast starter and many brewers will instead pitch additional dry yeast rather than creating a starter.
Since dry yeast cell counts vary by strain, yeast labs instead publish a recommended pitch rate for each yeast. This is typically expressed in grams per hecto-liter (100 liters) or g/hL. Many ales have pitch rates from 60-100 g/hL. Lagers are often in the 100-200 grams/hL range, wines in the 20-40 g/hL range and bacteria strains can either be very low or high depending on the specific variety.
Note that this is an “average” recommendation for the yeast strain. So if you are brewing an average strength ale and use an ale yeast with a recommended 75 g/hL then you can simply multiply that number by the batch size in hundreds of liters to get the grams needed. However if you are brewing a very high gravity beer more yeast may be needed so you will pitch at a slightly higher rate. Similarly a very low gravity beer would use a lower rate.
To apply these values simply calculate the batch size into the fermenter in hectoliters (100s of liters) and multiply that by the lab recommended pitch rate to get the number of grams to pitch. You can also use BeerSmith 4 to perform more advanced pitch calculations as outlined below.
BeerSmith 4 Dry Yeast Features
The new BeerSmith 4 software incorporates these lab recommendations in the yeast record under the Average Pitch Rate field for each yeast record. I entered the yeast pitch rate recommendations from the labs for each strain in the database so it is easily accessible. So you simply select the yeast you want to use and then it will show the recommended pitch rate and also the number of grams of dry yeast needed for the batch to achieve that rate. You can use the pitch rate slider to adjust that rate up or down for high or low gravity beers and it will adjust the grams of yeast needed. It also estimates the cells and pitch rate based on that, but overall you are best off starting with the lab’s recommended pitch rate and then adjusting up or down slightly if you are making a high or low gravity batch.
Note that the new feature only comes into play if you have the yeast quantity in grams using the new yeast database. If you are working with a legacy recipe where the yeast is in packages, you need to substitute and re-select the new yeast ingredient from the database to get the yeast in grams with the lab recommended pitch rates.
In BeerSmith 4 you also have the option to factor in viability. While dry yeast does not age rapidly like liquid yeast, this can be useful if you have a very old package of dry yeast. Also new in BeerSmith 4 is the ability to estimate yeast starters for dry yeast using the section at the bottom. It will show you a recommended starter size if you are not using enough yeast, and if you enter the same value or your own value into starter size used it will show the estimated cell counts for pitching. So you have the full range of options for dry yeast using the new BeerSmith 4 recipe builder.
If you want to learn more about the new yeast features in BeerSmith 4 you can visit an article on the yeast features here or watch the video tutorial on BeerSmith yeast features here.
I hope you enjoyed this week’s article on dry yeast pitch rates. Thanks for joining me on the BeerSmith Home Brewing Blog. If you want to take the guesswork out of brewing, please try my BeerSmith 4 recipe software from BeerSmith.com. Be sure to sign up for my newsletter or my podcast (also on itunes and youtube) for more great tips on homebrewing.
