Yeast extract, also known as yeast autolysate, is a common food ingredient used to provide flavor to sauces, soups, chips, crackers, and other savory foods. But like many food products, yeast extract has a shelf life and can go bad if stored improperly or kept past its expiration date.
What is yeast extract?
Yeast extract is made by autolyzing (self-digesting) yeast cells. This process breaks down the cell walls of the yeast, releasing amino acids, peptides, nucleotides, and other water-soluble components that provide the characteristic umami flavor.
Commercially produced yeast extracts are made by growing yeast (usually Saccharomyces cerevisiae) in a fermentation vat. Once the yeast has used up all the fermentable sugars, the cells are harvested, washed, and heat-treated to destroy any remaining enzymes. The yeast is then mixed with salt and heated again to break down the cell structures further. The resulting viscous, brown slurry is yeast extract.
Yeast extract is valued for its savory, meaty, umami taste. It contains high levels of glutamic acid, an amino acid that acts as a flavor enhancer. Yeast extract also provides vitamins and minerals from the yeast cells, particularly B vitamins like thiamine, riboflavin, niacin, folic acid, and biotin.
Does yeast extract go bad?
Yes, yeast extract can spoil and go bad over time. Like any food product, yeast extract has a limited shelf life. The shelf life depends on how the yeast extract is packaged and stored.
In the pantry: When stored in an air-tight container in a cool, dry pantry, yeast extract will keep for about 1 year past its printed expiration date before going bad.
Refrigerated: An opened container of yeast extract will keep for about 6-12 months in the refrigerator before spoiling.
Frozen: Yeast extract can be frozen to extend its shelf life significantly. Kept frozen at 0°F (-18°C) or below, yeast extract can keep for 2-3 years before deteriorating in quality.
How to tell if yeast extract has gone bad
Here are some signs that yeast extract has spoiled and is no longer good to eat:
- Change in texture – Fresh yeast extract should have a smooth, paste-like consistency. If it becomes thin and runny or has an overly thick, gritty texture, it has likely gone bad.
- Mold growth – Any mold or fuzzy growths on the surface of the yeast extract mean it should be discarded.
- Off odors – Yeast extract will start smelling sour, rancid, or unpleasant when it spoils.
- Change in color – The rich brown color of yeast extract can fade or darken when it goes off.
- Expiration date – If stored properly, yeast extract that is well past its printed expiration date should be discarded.
What causes yeast extract to spoil?
There are a few main factors that can lead to yeast extract going bad faster:
- Oxygen exposure – Yeast extract exposed to excess air oxidizes and deteriorates faster. Keeping the container tightly sealed prevents oxygen from speeding up spoilage.
- Heat – High storage temperatures accelerate yeast extract’s decline. Keep it in a cool pantry or refrigerator.
- Moisture – Dampness from high humidity can promote mold growth. Store yeast extract in a dry area.
- Contamination – Dirty utensils or repeatedly dipping fingers into the yeast extract introduces bacteria that will cause it to spoil quickly.
Can you eat yeast extract after the expiration date?
It’s not recommended to eat yeast extract after its printed expiration date. The expiration date is an estimate of when the manufacturer can guarantee the product will retain peak flavor and quality. Over time, the flavors and nutrients in yeast extract degrade.
However, yeast extract that is properly stored may still be safe and usable for a short period after its expiration date. Do a visual inspection and smell/taste test – if the yeast extract has maintained its normal color, texture, and flavor, it may still be alright to consume. But yeast extract that is more than 6-12 months past its date should be discarded.
Can spoiled yeast extract make you sick?
Consuming yeast extract that has spoiled is unlikely to cause serious illness in most people. However, eating or cooking with bad yeast extract can lead to upset stomach, nausea, vomiting, and diarrhea.
The biggest risk from spoiled yeast extract comes from potential microbial growth. Moldy or bacteria-laden yeast extract can contain toxins that lead to food poisoning symptoms if ingested. Infants, pregnant women, elderly people, and those with compromised immune systems are most susceptible to foodborne illness from eating spoiled foods.
How to store yeast extract properly
Here are some tips for maximizing the shelf life of yeast extract and preventing it from going off prematurely:
- Purchase yeast extract in small containers if you don’t use it frequently. Less air in the container means less oxidation.
- Check the manufacturing or ‘best by’ date and choose the freshest container.
- Keep yeast extract in a cool, dry spot. The refrigerator is ideal for opened containers.
- Seal the yeast extract container tightly after each use.
- Don’t dip utensils or fingers into the yeast extract, as this introduces bacteria.
- Use clean utensils to remove yeast extract each time.
- If the yeast extract seems thicker than normal, gently stir it before use rather than adding water.
- Freeze yeast extract for long term storage. Thaw in the refrigerator before use.
Can you freeze yeast extract?
Yes, you can safely freeze yeast extract to extend its shelf life. The freezer prevents yeast extract from oxidizing or having microbial growth. Frozen properly, yeast extract can keep for 2-3 years before the quality degrades compared to 1 year shelf life normally.
To freeze yeast extract:
- Make sure the yeast extract container is tightly sealed.
- Leave a little headspace in the container as yeast extract will expand slightly when frozen.
- Place the sealed yeast extract container in a freezer bag if desired.
- Freeze at 0°F (-18°C) or below. Consistent freezing temps are important for longest shelf life.
- Always thaw yeast extract in the refrigerator before use. Do not thaw at room temperature.
- Use thawed yeast extract within 1 week for best quality.
How to substitute spoiled yeast extract
If you discover your yeast extract has spoiled, don’t worry – there are a few good substitutes you can use instead:
- Soy sauce – Use 1 teaspoon soy sauce in place of 1 teaspoon yeast extract.
- Miso paste – Miso provides rich umami flavor. Use about 1/2 teaspoon miso per 1 teaspoon yeast extract.
- Fish sauce – Adds salty, briny notes similar to yeast extract. Use sparingly, starting with 1/4 teaspoon fish sauce for every 1 teaspoon yeast extract.
- Mushroom powder – Rehydrated dried mushrooms offer meaty umami taste. Use 1 teaspoon powder for 1 teaspoon yeast extract.
- Tomato paste – Contains glutamic acid like yeast extract. Use 1 teaspoon tomato paste for every 1 teaspoon yeast extract.
- Anchovy fillets – Puree 1-2 oil-packed anchovy fillets as a replacement for 1 teaspoon yeast extract.
For the best results, combine a few substitutions together. Soy sauce, tomato paste, and dried mushrooms can replicate the savory flavor of yeast extract when used in small amounts. Taste as you go when substituting to get the flavor balance you want.
Nutrition information of yeast extract
Here is the nutrition information for a 1 teaspoon serving of yeast extract:
| Nutrient | Amount |
|---|---|
| Calories | 5 |
| Protein | 0.5 g |
| Carbohydrates | 1 g |
| Fat | 0 g |
| Sodium | 75 mg |
| Sugars | 0 g |
| Glutamic acid | 400 mg |
| Riboflavin | 0.1 mg |
| Niacin | 2 mg |
Yeast extract is low in calories, fat, and carbs. It provides a range of B vitamins, amino acids, and umami flavor from glutamic acid. Using yeast extract allows you to add savory taste without extra calories, sodium, or fat.
How to use yeast extract
Here are some tips for incorporating yeast extract into recipes:
- Add to sauces and gravies for meaty flavor. Start with 1/4-1/2 teaspoon per cup of liquid.
- Mix into dips, spreads, dressings, and marinades. Goes well with anything savory.
- Stir into stews, chili, casseroles, and braised meats.
- Add to rubs and breadings for roasted vegetables or fried foods.
- Use in place of salt when cooking grains like rice, barley, and farro.
- Mix into ground meat dishes like burgers, meatloaf, and meatballs.
- Make gluten-free gravy by whisking yeast extract into veggie or mushroom broth.
Always start with small amounts of yeast extract and add more to taste. A little bit goes a long way in providing rich, savory flavor.
Conclusion
Like many pantry staples, yeast extract has a finite shelf life. Exposure to air, heat, and bacteria cause it to spoil over time. Signs of spoiled yeast extract include changes in texture, smell, and appearance. Eating rotten yeast extract can cause minor stomach upset in healthy adults.
Proper storage is key to maximizing yeast extract’s shelf life. Keep it sealed in a cool, dry place and refrigerate opened containers. The freezer can extend shelf life for a few years. Check packaging dates and use opened yeast extract within 6-12 months.
Substitutions like soy sauce, miso, and tomato paste can provide similar savory flavor if yeast extract goes off unexpectedly. When stored and handled properly, yeast extract can be used to add delicious umami taste to recipes for months after opening.
