Does the brewer’s yeast go bad?

In this brief guide, we are going to answer the question “does the brewer’s yeast go bad” with an in-depth analysis of whether or not brewer’s yeast goes bad. Moreover, we are going to discuss the proper way to store the yeast and the ways to spot yeast that has gone bad.

Beer is the most popular alcoholic beverage worldwide, and the third most consumed after water and tea. Global beer production has risen in the last decades, reaching 1.95 billion hectoliters in 2017 (1).

So without much ado, let’s dive in and figure out more about it.

Does the brewer’s yeast go bad?

Yes, like all other food items, brewer’s yeast also goes bad after a certain time. When we say that brewer’s yeast goes bad, what we are referring to is that its potency and effectiveness would have degraded. The best way to tell this is by reading the mentioned “best before” date on the label. After this date, the yeast might still be safe to use but its quality starts to deteriorate.

Brewer’s yeast is made from the Saccharomyces Cerevisiae and is used in beer and wine production. If properly stored, it lasts for a long time.

Drying yeast biomass enhances shelf life of food products. In the case of probiotic yeast biomass, the freeze-drying process is usually applied, since this type of drying saves the living cells. The moisture content of food powders is usually between 2% and 8%. At this level, powders are stable with an average shelf life of 12–24 months (2).

What is the nutritional profile of brewers yeast?

Brewer’s yeast is also called nutritional yeast, a probiotic that helps in the process of digestion. Moreover, it can also serve as a nutritional supplement as it is rich in selenium, potassium, iron, zinc, protein, chromium, and magnesium, according to the USDA.

According to the Food and Agriculture Organization and the World Health Organization, a probiotic is “a live microorganism which, when administered in adequate amounts, confers a health benefit to the host”. Lyophilized yeast is a probiotic yeast used worldwide for the prevention and treatment of diarrheal diseases (1).

Moreover, it also contains many vitamins like thiamin, riboflavin, niacin, pantothenic acid, pyridoxine, folic acid, and biotin.

How to store brewer’s yeast?

Brewer’s yeast should be stored in a cool, dry, and dark place away from direct sunlight, heat, and moisture. Unopened dry brewer’s yeast lasts for about 12-2418 months or even more when stored in a cool, dry, and dark place away from direct sunlight, heat, and humidity. Thus, you can store an unopened pack of brewers yeast in a cool and dry corner of your pantry.

Opened packages of brewer’s yeast should be stored in an air-tight container or plastic zipper bag in the refrigerator to preserve its freshness for a long time.

It is worth mentioning that the sunlight, oxygen, and moisture can degrade the quality of the brewer’s yeast and can also shorten its shelf life therefore care should be taken while handling the yeast.

A food unfit for consumption may not necessarily be spoiled and may contain a high number of food poisoning causing bacteria. Microbial deterioration of food is evidenced by alteration in the appearance (color changes, pockets of gas/ swelling), texture (soft & mushy), color, odor, and flavor or slime formation. In dry food products, microbial growth is reduced due to low water content, and chemical changes not induced by microbial or naturally occurring enzymes may occur. These changes usually involve O2, light and other than microbial spoilage, are the most common cause of spoilage e.g. oxidative rancidity of fats and oils (3).

Can open brewer’s yeast be stored in the fridge?

Yes, opened brewer’s yeast can be stored in the fridge. Dry brewer’s yeast lasts for about a year in the fridge when kept at or below 40 °F in an air-tight container or plastic zipper bag. Refrigeration increases its shelf life, as long as the product is free from moisture and oxygen. Refrigeration slows both the growth of unwanted microbes and the oxidation process. Indeed, the rate of chemical reaction in general, including oxidation, decreases as the temperature decreases (4).

When it comes to fresh brewer’s yeast, it has a short shelf life and should be used within 10 days (8).

Can the brewer’s yeast be stored in the freezer?

Yes, the brewer’s yeast can be stored in the freezer and the frozen brewer’s yeast has a longer shelf life than its counterparts. It can be stored in a plastic freezer bag or air-tight container in the freezer for years but we recommend you to use the brewer’s yeast within 6 months to enjoy its best quality. In the freezer, most food can stay safe indefinitely but risk losing the properties that make the foods enjoyable, such as texture, flavor, and hydration (4).

Other FAQs about Yeast which you may be interested in.

Can you bake bread with nutritional yeast?

Can I use yeast instead of baking powder?

Is unopened brewer’s yeast safe to use after “best by date?

There must be written the “best by” or “best before date” written on the package off the yeast, but you should always keep one thing in mind that the “best before” or the “best by” dates are mainly focused on the quality rather than the safety. Thus you will get the best quality of the yeast within the “best by” or “best before date” but you can still use the unopened, properly stored dry yeast even after some time from this date (6). 

Many canned and boxed products are safe to eat long after the date on the container and the shelf life of refrigerated and frozen foods can be extended if they are handled properly. Once a perishable item is frozen, it doesn’t matter if the date expires — foods kept frozen continuously are safe indefinitely, though the quality slowly deteriorates over time (5). 

How to tell if the brewer’s yeast has gone bad?

In general, higher temperatures of storage, along with exposure to moisture, oxygen and light enhances chemical changes such as lipid oxidation, caking and browning, which limits the shelf life and leads to nutrient loss of powdered food products (7).

If you notice the dry brewer’s yeast clumping together, or if there are large lumps present in the yeast, or if there are any signs of organic growth in the container of yeast, then it is an indication that your yeast has gone bad. 

Moreover, if the color of the brewer’s yeast darkens (from beige to more of a grey one) then it is the indication that your brewer’s yeast has gone bad. The dark color indicates browning due to Maillard reactions. Lipid oxidation leads to the formation of off-odor and off-flavor components in the food (7).

How can you tell if yeast is still good to use?

So what you can do to check the efficiency of the dry yeast is to take ¼ cup of warm water and add 1 tsp of sugar to it. Afterward, add 2¼  tsp of brewer’s yeast to it or you can add an envelope of yeast to it. Let it stand for approximately 10 minutes. If you see the foam formation in the water after 10 minutes, then it is the indication that the yeast is still good to use.

Tips to keep the brewer’s yeast fresh for a long time

1. In the case of the unopened dry brewer’s yeast, you should store it in a cool, dry, and dark corner of your pantry or kitchen cabinet away from direct sunlight and heat.
2. You should never store brewer’s yeast in a humid environment.
3. You should always store the opened brewer’s yeast in an air-tight container or plastic zipper bag at or below 40°F in the refrigerator.
4. You should not use a wet spoon to scoop out the dry yeast.
5. Close the lid of the jar as soon as you scoop out the dry yeast so that the moisture won’t find its way in your yeast and spoil it.

Conclusion

In this brief guide, we answered the question “does the brewer’s yeast go bad” with an in-depth analysis of whether or not brewer’s yeast go bad. Moreover, we discussed the proper way to store the yeast and the ways to spot yeast that has gone bad.

Citations

1. Sampaolesi, Sofía, et al. Potentiality of yeasts obtained as beer fermentation residue to be used as probiotics. Lwt, 2019, 113, 108251.
2. Jach, Monika E., and Anna Serefko. Nutritional yeast biomass: characterization and application. Diet, microbiome and health. Academic Press, 2018. 237-270.  
3. Dilbaghi, Neeraj, and S. Sharma. Food spoilage, food infections and intoxications caused by microorganisms and methods for their detection. 2007.
4. Anderson, E; Li, J. Preservatives and Refrigeration. Michigan State University. 2021.
5. Shelf Life of Food Bank Products. Carnegie Mellon University. 
6. Gravely, M. Before You Toss Food, Wait. Check It Out! Food Safety and Inspection Service. USDA. 2022.
7. Tehrany, Elmira Arab, and Kees Sonneveld. Packaging and the shelf life of milk powders. Food packaging and shelf life, a practical guide. CRC Press, Boca Raton, London, 2010, 127-141.
8. Reed, G., Nagodawithana, T.W. 1991. Baker’s Yeast Production. In: Yeast Technology. Springer, Dordrecht.