Yeast can be a finicky devil. Common troubles distillers encounter includes a wash that doesn’t start fermenting, a blue or cloudy product, or not as high ABV (alcohol by volume) as you wanted in the final yield – sometimes fermentation never takes off. To avoid fumbles with your product due to yeast issues, pay close attention to temperature, thermostat viability, and timing, as well as these insider tips from one of our yeast vendors, WhiteStar, to get you to perfect pitch.
1. Be Choosey
Make sure your yeast is specifically made for “high gravity” and “high alcohol” fermentations. This ensures that your yeast can handle the amount of fermentable nutrients you start with, which for craft distillers is usually high. The yeast should be labeled to ferment ABV 12-20%. This will allow you to maximize your yield in a short amount of time with optimum fermentation nutrition.
A note on high rye: High rye or high-protein mashes tend to suppress yeast activity. Try adjusting enzymes to the mash to break down the proteins so that the yeast doesn’t suffocate.
2. Make Sure She’s Single, But Don’t Let Her Mingle
The strain of yeast you use affects the flavor profile of your product. If you make sure to use a single, pure yeast strain, you’ll be able to replicate your product as many times as you want. Brewers will sometimes use multiple strains to increase the complexity of their flavor profile, but in distilling spirits, one pure strain works best.
A note on purity: Keep an eye on the PH-level of your mash. If it changes suddenly from a 4 to 2 in one day, it is an identifier of contamination, which is not good for the lifespan of your yeast no matter how pure the strain.
3. Pour More for Round Two
If you’re re-pitching yeast, increase the quantity by at least 10% when it has reverted to a slurry. It isn’t recommended to reuse yeast for more than three cycles for whiskey and rum strains; this can compromise the microbiological integrity of your yeast. The key is to keep the viability and relative sterility of the yeast intact. Some high gravity neutral grain yeast doesn’t do well with repeated use, since additional phosphate based macro nutrients are required to achieve an ABV above 16%.
4. She Can’t Breathe Without You
After 30 minutes of pitching, aeration is recommended to ensure full mixing and oxygenation of the mash and yeast. Aerate and mix daily, particularly for higher gravity fermentations. Another way to give yeast what it wants is to add nutrients that increase nitrogen levels.
5. Shiver Me Nutrients
To increase your spare yeast shelf life, keep it at colder temperatures; dry yeast will retain more of its viability and activity over time than if it’s kept warm. If you intend to use your yeast in the near future, though, it is best to keep it at room temperature. Taking the freeze dry path? Let it warm completely to room temperature in the package before rehydration and pitching. Has it been on the shelf for a while? It may be necessary to rehydrate for as long as 30 to 60 minutes.
A note on temperature and timing: your yeast should be room temperature, but your mash should also be at the right degree. Your mash should boil before adding the yeast in order to stop enzymes from interfering with yeast activity. However, mash that’s too warm won’t allow the yeast to thrive, and waiting too long to add the yeast will increase the likelihood of contamination.
To make sure you’re doing what’s best for your mash, make sure you’re familiar with the instructions that each yeast vendor recommends on their packaging.
Wondering which nutrients work best for the product you have in mind? Our inventory experts can guide you in picking yeast, nutrients, or enzymes, or answer any questions you might have about their specs. Let’s get started.