How To Tell If Tempeh Is Bad? (3 Warning Signs)

Since tempeh is a lesser-known tofu alternative globally, one of the frequently asked questions about this soy product is “How to tell if tempeh is bad?”. 

Whether you buy it from a reliable supplier or it’s been lying on your refrigerator shelf for a while, you must look through this article to avoid consuming the low-quality tempeh, or at least understand how long does tempeh last.

What Is Tempeh?

Tempeh is a tofu substitute made from fermented soybeans, giving it an excellent source of probiotics. This is part of what makes the product unique while also being extremely nutritious. 

Although it is workable to make your tempeh yourself, you don’t have to do so. Because while it’s not as popular as tofu, you can usually buy it for a fair price at your local health food shop.

We combine soybeans with a “tempeh starter” to make tempeh. The starter is a mold spore known as “Rhizopus.” It may seem disgusting, but it is entirely safe. This culture bonds to the soybeans to form the tempeh bread. 

The Aging Process Of Tempeh

Naturally, any fermented product must get aged for a length of time. But how to tell if tempeh is bad or how long does tempeh last?. When the tempeh is at its freshest, it is usually white. It should smell like yeast or mushrooms, according to many people. It should be sturdy as well. That is the reason why people used it as a mushroom substitution.

It may have a gray hue or grow some grey patches after a few days in the fridge. But, don’t get stressed out! Because tempeh, which is known as moldy tofu, contains live cultures, they continue to live and grow even after we prepare the tempeh.

Always bear in mind that your tempeh is probably fine if it smells good, is firm, and is white or gray.

What Are Tempeh Black Spots?

Black spots on tempeh are a byproduct of the fermentation process, which is required for the production of tempeh. We will describe the fermentation method used to create tempeh in the steps below:

First, to get the texture, you must cook the soybeans.

Second, remove the hull from the soybean because it is a by-product of the seeds, and humans cannot consume it.

Third, after cooking and cooling the soybeans, they should be placed in a tray with Rhizopus to produce the binding mold, mycelium. This tempeh binding mold is to keep the tempeh together.

Then, to allow the fermentation procedure to bind, keep the mixture at a constant temperature.

Finally, the Rhizopus will create black spores, signaling the end of the fermentation process.

The tempeh continues to ferment as it rests in the fridge, causing the black spores to emerge. When the tempeh has developed black spots all over it, it is fully mature and has its best flavor.

The tempeh has fully developed and attained its optimal flavor when the spores on the surface have turned black. If you detect any further mold growth or development from these areas, harmful germs may have formed, and you shouldn’t consume the tempeh. 

Do not worry about any black spots that appear before the expiration date. If you’ve ever glanced at the underside of a mushroom, you’ll see that its spores and that of the tempeh are pretty similar, and both show reproduction. This is just a visual sign of Rhizopus fungus proliferation.

How To Tell If Tempeh Is Bad?

How To Tell If Tempeh Is Bad

It is not terrible if your tempeh has black spots (or grey and white). Because tempeh ferments and incubates at constant temperatures, you’ll typically notice this if you leave it in its container.

However, the dark spots on your tempeh might be a diversion from true rotting, which is more difficult to detect.

There are a few crucial indications to be cautious of after 7-10 days that may tell the tempeh has gone bad:

1. Smell 

Just by using your nose, how can you assess a fermented food that might already have a strong odor? In fact, the smell of your tempeh should be nutty and earthy, but not too strong. 

If you can smell the tempeh from a distance, it’s probably gone bad. If your tempeh smells rotten or has strong overtones of alcohol, or ammonium, it’s time to get rid of it.

Other bacteria grow quickly on your tempeh, causing these odors. To avoid this, keep your tempeh dry and freeze it on your refrigerator shelf until you’re ready to use it.

2. Texture

Tempeh is created from soybeans that will have a layer of white mycelium. If we ferment it correctly, this edible mold will grow between the beans.

Make sure the mold has entirely grown over the beans, with no gaps or regions where the mold has not formed when purchasing your pieces of tempeh.

3. Dark bean coloring

Although dark bean coloring is another symptom of rotting, tempeh made from black beans should have a dark hue as a secondary signal when inspecting the tempeh. If you’re making the tempeh using black beans, don’t worry about this.


Here are some frequently asked questions that we have collected while researching this object.

How To Tell If My Tempeh Is Still Good To Eat?

The white, fuzzy surface of new tempeh signifies that the mold is active and the food is still fermenting, yet it is in its “healthiest” state. 

Because we are fermenting tempeh with live cultures, the mold will eventually expire or destroy itself. Therefore, firm tempeh with a yeasty or mushroom-like fragrance is ideal.

Can I Eat Tempeh With Dark Spots?

Tempeh is a soy-based food with a rich and nutty flavor that is a fantastic substitute for tofu and a superb source of protein. Unfortunately, the development of spores in the fermentation with the Rhizopus mold used to create tempeh causes black spots to appear.

Because tempeh is made with a bacterial starter, determining when it is ready to consume and when it is past the point of spoiling may be difficult. If your tempeh has dark spots, it is safe to eat. You don’t have to worry about dark spores with tempeh because it’s composed of useful mold.

It requires healthy mold for the production of tempeh. Understanding the signs of edible vs rotten tempeh will keep you safe and help you avoid wasting food.

The following are signs of spoilage:

  • Awful smells.
  • The texture is slimy, sticky, or mushy and soft.
  • Beans turn dark brown.
  • Discoloration of pink.

Is Eating Raw Tempeh Possible?

Can you eat tempeh raw? Yes, you can eat uncooked tempeh and still keep all of its nutritional value, but pay attention to some minor details.

Cooking significantly diminishes vitamin levels while bringing out all the flavors! People usually serve tempeh prepared, either fried, steamed, or boiled.

What Are Tempeh Side Effects?

Tempeh, like other fermented soy products, is safe for most individuals. Yet, some people may choose to limit their tempeh consumption because of several reasons.

Those who are allergic to soy should avoid tempeh completely because eating tempeh may cause symptoms such as rashes, edema, or difficulty breathing.

Though studies show that soy consumption has little influence on thyroid function, persons with thyroid problems should limit their intake.

How To Store Tempeh Properly?

We cannot deny that tempeh is so delicious and good for health. As a result, we’ll need to consider several options for storing this superfood.

There are two feasible ways to keep tempeh last longer:

  • Seasoning tempeh with garlic and salt: This is an effective technique to extend its shelf life. These spices act as natural preservatives, allowing the tempeh to last longer than it would.
  • Freezing tempeh: By storing tempeh in the refrigerator, you may easily extend its natural shelf life. Keeping it at room temperature is a bad idea that will lead to a slew of issues later. 

However, before placing the tempeh in the fridge, make sure it’s in a safe and contained plastic container. It should last at least a week if you do it this way.

Following these steps to freeze tempeh:

First, put tempeh in a safe and contained plastic bag and make sure it’s well-packed that the container isn’t too full.

Second, freeze it at freezing temperature.


Although tempeh is lesser known than other soy products, it is relatively inexpensive and straightforward to prepare. Therefore, you may try it a few times with little danger.

We hope detailed information about tempeh in this article will help you answer the question: “How to tell if tempeh is bad?”. If you’re buying tempeh for the first time, make sure to check the expiration date and use it within a day or two after receiving it. 

That way, you’ll be able to get the hang of it and be more confident the following time around. You’ll be eating it constantly before you know it.

Kevin Richard

Hi all! I’m Kevin. I spend plenty of time in the kitchen every day because I love cooking healthy and delicious foods for my family and friends. Cooking gives me a chance to be creative and fun. It’s also one of the most meaningful ways to express my love and take care of my little family.

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