Does Your Fermentation Have Enough Vitamin Z?

Yeast are fundamental to brewing, and a healthy fermentation needs lots of nutrients.

Problems during fermentation tie up your tanks for longer and lead to lower beer quality. There are many possible causes of these problems, including a lack of nitrogen, oxygen, or minerals—but one of the most common issues is a lack of zinc. While there is typically enough nitrogen in wort, the same can’t be said of zinc, and a deficiency in that mineral runs the risk of off-flavors. The presence of zinc supports yeast growth, sugar conversion, healthy fermentation, yeast viability, and flocculation. If possible, brewers should measure the concentration of zinc before fermentation begins.

Not only is zinc deficient in wort, but its concentration gradually decreases during the mash and brewing process. Most of it remains with the spent grains or is lost at protein break or when the wort is clarified. Yet not having enough leads to sluggish fermentation, while optimizing the zinc levels in wort stimulates the yeast’s ability to metabolize maltose and other sugars.

Why Is Zinc So Important to Brewing?

Most yeast strains require 0.3–0.5 mg/L of zinc for optimum fermentation, but wort typically provides less than that. Yet having enough helps to improve the rate of fermentation and avoid stalled fermentations. In the first hours of fermentation, yeast cells absorb the zinc, which accumulates in the vacuoles of the yeast cells.

In zinc-deficient wort, common off-flavors include acetaldehyde, diacetyl, and sulfur compounds.

Healthier Yeast Make Better Beer.

Yeast that have absorbed zinc are more robust, able to complete fermentation more rapidly, with better flocculation and with lower risk of off-flavors. It’s well known that healthier yeast make better beer, thus the brewer should provide the best possible environment for the yeast to grow and ferment happily. Furthermore, healthy fermentations save the brewery money by freeing up tanks sooner, and the yeast is healthier for harvesting and re-pitching afterward.

The Benefits of Proper Zinc Concentration

• Faster fermentations translate to more production capacity.
• Better yeast flocculation translates to reduced filtration and conditioning costs.
• Healthier yeast for harvesting means less spent on fresh pitches.
• Better foam stability means a more attractive beer that sells.

Where Does the Zinc in Brewing Come from?

1. Malt

Malt is a natural source for zinc. However, during the mash, the concentration of zinc gradually decreases until only a small amount is left. Only about 5 to 20 percent of the zinc found in malt remains in the wort after mashing, and the amounts dissolved are highly variable.

2. Water

The level of zinc in drinking water is less than 1 ppm, typically near 0.05 ppm.

3. Nutrient Additions

Brewers always need to consider whether it’s necessary to add nutrients. Since the amount of zinc that ends up in wort is unpredictable and tends to be low, it’s worth considering a zinc addition. It’s important for the synthesis of proteins, growth of yeast, and many aspects of fermentation. Forms of zinc that can be added include inactive yeast that are high in zinc or a zinc salt. Again, the recommended zinc level is 0.3–0.5 ppm. Lower concentrations risk poor fermentations and off-flavors.

When to Add Zinc?

1. For High-Gravity Fermentations

When wort has a higher gravity—more than 1.060 or 15°P—providing the optimal amount of zinc will help reduce stress on yeast and boost their alcohol tolerance. Zinc is important to yeasts’ cell cycle and a co-factor in the enzymes responsible for alcohol production. Optimal zinc content has a positive impact on fermentation that leads to a stronger beer at the end.

2. When Re-Pitching Yeast

The use of zinc and other nutrients helps to guarantee healthier yeast pitches for the next batches.

3. When Brewing with Sugars and Other Adjuncts

Since malt is a natural source of zinc, a wort made with less malt and more non-malt sugar sources means a greater need to supplement it with zinc.

The Solution

Ensuring an optimum concentration of zinc is key to a healthy fermentation. However, too much of it is toxic to yeast growth, so measuring or properly estimating the concentration is important.

For zinc-deficient wort, BrewNutri-Z is a good choice. From Angel Brewing, BrewNutri-Z is an inactive yeast with high zinc content. Deactivated yeast provide the nutrients that live yeast need to grow.

The effect of BrewNutri-Z on yeast sedimentation

When to Add BrewNutri-Z?

Zinc’s availability to yeast varies depending on when it is added. As one of the most important nutrients, zinc should be added just before pitching the yeast. Because too much zinc is bad for yeast, it’s essential to add a small, measured amount:

1. Add some in the final minutes before the end of the boil.
2. And/or, add some directly to the fermentor once the wort is cool.

About Angel Brewing

Based in China, Angel Brewing focuses on providing microbial products and fermentation solutions worldwide for brewing and other industrial applications, including wine production, distillation of spirits, fermented foods, biofuels, and more.

About Our Distilled Spirits and Biofuels Division

Angel can provide brewing yeasts, ingredients, and related technical services for the production of wine, beer, and other alcoholic beverages. All our products are natural, safe, and of high quality. Given the current energy shortages around the world, the production of ethanol fuels via yeast fermentation is an inevitable trend—but that’s only part of what we do.

About Angel

Angel specializes in yeast and biotechnology. Our business includes yeast, baking, yeast extracts, nutrition and health, and biotechnology. We’re one of the world's leading companies in the yeast industry, with 12 subsidiaries and products and services in more than 150 countries and regions.

For more information, please contact:
Ryan Wu
Angel Yeast Co., Ltd.
Yichang, Hubei, China
Tel.: +86 717 6353619
Email: [email protected]
Or visit: en.angelyeast.com