If you’re new to tempeh as a plant-based protein, you may be concerned by its unique appearance. After all, we’re usually told to avoid foods that look fuzzy or have dark spots!
Tempeh is safe to eat when fresh, but how can you tell whether it’s gone bad? As a vegan registered dietitian, I’ll discuss everything you need to know about so you can confidently enjoy this nutrient-dense food.
What is tempeh?
Tempeh is an Indonesian food made from fermented soybeans pressed into a dense cake. Soybeans are inoculated with the fungal mold Rhizopus oligosporus and then fermented, producing a dense block that can be sliced, cubed, or crumbled.
Tempeh is one of the best sources of protein for vegans with an incredible 34 grams of plant-based protein per cup, making it a popular food for plant-based eaters.
RELATED: Is Tempeh Gluten-Free? What You Need to Know
Does tempeh go bad?
Whether pasteurized or unpasteurized, tempeh will eventually expire just like most foods. As a result of the inoculation and fermentation process, it naturally has a fuzzy white appearance and may contain some black spots. This is normal and doesn’t mean that it’s unsafe.
Most tempeh in grocery stores has been pasteurized to kill potentially harmful bacteria. Pasteurized tempeh can last for weeks to months in the refrigerator after you purchase it, as the “Sell By” date is often months in advance.
Fresh tempeh, which can be found at some farmer’s markets and specialty retailers, usually lasts for 7-10 days in the fridge. Refrigeration will slow down the fermentation process, but won’t stop it completely.
Frozen tempeh will last for about 2-3 months before the quality starts to degrade.
LightLife, one of the leading tempeh brands, doesn’t recommend eating their products past the “Best By” or “Sell By” date in their FAQ. This isn’t the same as an expiration date, so pasteurized tempeh is likely still safe for about 2-3 weeks after this date, but it will start to degrade in quality.
Tempeh that is safe to eat will have:
- A fuzzy white mycelium (Rhizopus growth)
- Possible black or dark gray spots
- A firm, dense texture
- A mild mushroom or earthy aroma that isn’t unpleasant
- Beige-colored soybeans
RELATED: Can Vegans Get Food Poisoning?
Signs of spoilage
If you notice any of the following signs, it’s best to throw your tempeh out:
- Slimy texture
- Strong, unpleasant odors
- Mold growth in off-colors like pink or green
- Soft texture, no longer firm/dense to the touch
- Dark brown soybeans lacking the white fuzzy mycelium
Storage tips
To keep your tempeh as fresh as possible, follow these food storage guidelines:
- Store fresh (unpasteurized) tempeh in an airtight container in the fridge for 7-10 days, unless you notice signs of spoilage earlier than this (per Holy Tempeh FAQ).
- Store unopened (vacuum-sealed & pasteurized) tempeh in the fridge for up to 2-3 weeks following the “Sell By” date.
- Freeze for 2-3 months if opened, or up to a year if kept in the original vacuum-sealed packaging (per LightLife FAQ).
- If freezing, do so before the “Best By” or “Sell By” date for best quality.
- Thaw frozen tempeh in the fridge, not on the counter or in the sink. Thawing frozen food at room temperature makes bacterial contamination more likely.
Summary
Its fuzzy white coating and dark spots may make tempeh look “off” when you purchase it, but rest assured that this is normal and safe. You’ll know it’s rotten when you notice a slimy texture, pink or green mold, strong and unpleasant odors, or soybeans that have turned from beige to dark brown.
Fortunately, following proper food storage guidelines can help make tempeh last longer.
Struggling to find a tempeh recipe you enjoy? My Sticky Sesame Tempeh is a sweet-and-spicy take that makes for an easy weeknight dinner or meal prep!