Zinc plays a vital role in yeast health and fermentation. It’s an essential nutrient that supports yeast metabolism—but when present in excess, it can become toxic and lead to undesirable metallic off-flavors in your beer.
How does Zinc affect your beer?
Zinc helps promote healthy yeast activity by accelerating fermentation and preventing stuck fermentations. It supports the yeast cell cycle, making it crucial to a successful brew. Fortunately, malt naturally contains zinc, and some of it is extracted during the mash—especially when the mash pH is on the lower end.
However, excessive zinc levels can harm yeast and disrupt fermentation. Too much zinc can also introduce harsh, metallic notes that negatively impact flavor.
Zinc Amounts in Brewing Water
While Zinc is beneficial to fermentation and yeast health, it should be in very small concentrations. The ideal range for Zinc in brewing water is 0.1 to 0.2 ppm for improved fermentation.
If zinc has levels below 0.1 ppm like with reverse osmosis water, then a zinc supplement will need to be added to assist the fermentation.
At zinc levels above 0.5 ppm, the beer will have negative taste.
Testing your Water’s Zinc Levels
To determine the zinc concentration in your water, you should use the CraftPro Master Brewer’s Test Kit.
The CraftPro In-Lab test kit will let you send in a sample to our laboratory to have it tested for zinc and 14 other parameters that are critical to brewing such as magnesium, chloride, and sulfate. As well as two brewing specific calculations that affect your water profile.
The CraftPro Master Brewer’s Test Kit makes it easy to get your results. After you order your test kit you’ll get everything you need to collect a sample and send it to our lab. Once we analyze your sample, we’ll send you an easy-to-read, electronic report with exact concentrations and calculations done for your sample.
How to reduce Zinc concentrations in brewing water
Reverse Osmosis Filtration has become extremely popular in the brewing community. This is because it will take your water profile to a blank slate. This is an effective way to remove everything you do not want in your water, but it will also remove everything beneficial.
If you are using a reverse osmosis filtration system, you will need to build your own water profile by adding the minerals back in. If you do not know where to start, you can look at our brewing profiles page to see what many popular brewing cities have as their default water.
Buying Distilled Water
If you do not want to install a filter or have access to one, but your zinc levels are too high to brew with, you can always buy RO or distilled water instead of filtering it yourself. This will be the same process as building back your own water profile with an RO system.
What to do if Zinc levels are too low
If you are using reverse osmosis or another water source with less than 0.1 ppm, then zinc supplements will be needed. This can be done using a zinc salt like zinc chloride.
Typically a very small amount of this will be necessary, there are many online brewing calculators you can use that will help you find the correct amount you need to add to get to your desired concentration.
Conclusion:
Zinc plays a critical role in the fermentation process and can help prevent stuck fermentations when in the proper concentrations. But too much can be toxic to yeast and create off, metallic flavors. Filtration or zinc salts can be used to control the concentration of zinc in your water profile.
