Every brewer knows that yeast needs sugar, oxygen, and the right temperature to ferment well. But one of the most critical micronutrients for yeast performance rarely gets the attention it deserves: zinc. ## Why zinc matters Zinc is a cofactor for over 300 enzymes in yeast cells. It plays a direct role in cell growth, stress resistance, and fermentation metabolism. One of the most important zinc-dependent enzymes is alcohol dehydrogenase (ADH), which catalyses the final step in ethanol production. Without adequate zinc, this pathway slows down. Zinc also supports maltotriose fermentation, the uptake of the largest fermentable sugar in wort. When zinc is deficient, maltotriose is often the last sugar to be consumed, and in some cases it is left behind entirely, contributing to incomplete attenuation. Research has shown that wort zinc levels below 0.1 ppm are associated with sluggish fermentations. The target range for healthy fermentation is 0.15 to 0.30 ppm. ## The boil problem Here is the challenge: yeast scavenge zinc very early in fermentation, pulling it out of the wort within the first hours of active growth. But the wort itself has already lost much of its zinc content during the boil. Hot-side zinc additions (adding zinc to the kettle) do not survive the boiling process in bioavailable form. This means that even if you are adding zinc to the kettle, the yeast may not be able to use it. Cold-side dosing, adding zinc directly during fermenter fill, is the only reliable way to ensure bioavailable zinc reaches the yeast when they need it most. ## What brewers are seeing The results from breweries using cold-side zinc supplementation speak for themselves. Range Brewing reported approximately 4 days faster fermentation after adding zinc to their process. KAIJU! Beer saw their West Coast IPA reach final gravity in 21 days with zinc, compared to 29 days without. That is 8 days of freed-up tank capacity from a single addition that costs less than 1 cent per litre. ## The repitch connection Zinc supplementation becomes even more important for breweries that repitch yeast. Every boil destroys nutrients. Every repitch compounds the deficit. Without replacing what the boil takes out, each successive generation of yeast starts at a disadvantage. Cold-side zinc dosing on every batch, including repitch batches, restores what the boil removes and keeps yeast performing consistently across generations. ## Getting started Bluestone Yeast Zinc Booster (BSY-N01) is a sterile liquid zinc supplement designed for cold-side addition during fermenter fill. The standard dose is 10 mL per hectolitre, targeting 0.2 ppm wort zinc. For high gravity worts, double the dose. For non-malt or adjunct-heavy worts, dose at 15 mL per hectolitre. It works with any yeast, including dry yeast. No changes to your existing process beyond adding one bottle during fermenter fill. --- Want to improve your fermentation performance? Learn more about our Nutrient Booster range or book a discussion to talk about your brewery’s needs.