Why Is Tempeh Bitter? (Solved!)

Bitterness is the most common complaint about the flavor of tempeh.

Therefore, many ask – why is tempeh bitter? Tempeh can come out bitter when adding vinegar to the fermentation process. Allowing tempeh to over-ferment can also cause bitterness.

Fermentation can be an unpredictable process and different brands of tempeh can vary widely in their bitterness, even when they use the same ingredients.

Tempeh’s bitterness is extremely common, but luckily, is also fixable and avoidable.Let’s learn how to prevent, remove, and solve bitter tempeh once and for all.

Is Tempeh Supposed to be Bitter?

No. Finished tempeh should not be especially bitter.

The flavor of good tempeh is more reminiscent of some cheeses, with a nutty, mildly mushroomy, slightly funky flavor.

However, there are many opportunities for bitterness to creep in while tempeh is made, which means that it can often have a less pleasant flavor.

What Makes Tempeh Bitter?

There are two main reasons that tempeh can come out bitter:

Vinegar (Type, Amount, and Timing)

Vinegar is always added during the tempeh fermentation process.

Creating an acidic environment prevents many common harmful bacteria from growing in the tempeh, but tempeh starter spores thrive in an acidic environment.

Many tempeh recipes call for adding vinegar at the beginning during soaking, later as you cook the soybeans, or after cooking before fermentation.

When manufacturers make tempeh, they may use different types of vinegar or introduce it at different times during the process.

The type, amount, and timing of vinegar to your tempeh can contribute to a bitter flavor at the end.

Acetobacter (A Byproduct of Fermentation)

As tempeh ferments, the Rhizopus spores thrive and grow, binding the beans together into a firm cake.

However, during the fermentation process, other naturally occurring microorganisms can also be present in the tempeh.

Lactic acid is naturally present in soybeans in small amounts, and acetobacter is a natural companion to vinegar.

When tempeh is fermented for too long, the mushroomy flavor of the Rhizopus can subside, allowing the flavors of lactic acid and especially acetobacter to become more dominant, creating a bitter flavor.

Over-fermentation is the most common cause of bitterness in tempeh, but bitterness is also partly determined by how vinegar is used during the cooking process.

How Do You Get the Bitterness Out of Tempeh?

If your tempeh is bitter, steaming it before cooking will remove the bitterness and any unpleasant flavors that may be left over from fermentation (if you don’t mind the bitterness, note that you can eat it raw).

To steam tempeh, cut it into chunks and place it in a steamer basket over boiling water for 10 minutes. You can also place chunks of tempeh in the microwave for 5 minutes.

Heat and steam will allow the bitterness to evaporate and dissipate before you use your tempeh in a recipe, and also makes it more receptive to other flavors as you cook with it.

Some people recommend boiling or soaking tempeh in hot water to remove any bitterness.

You can use this method if you like, but you may want to then dry the tempeh before cooking it further. Wetness will prevent browning and crisping as you cook.

Tips for Preventing Your Tempeh from Getting Bitter

If you are making your own tempeh at home, here are some tips to help prevent bitterness:

Don’t Soak the Beans in Vinegar

While some recipes may call for soaking soybeans in vinegar prior to cooking them for tempeh, this method is strongly associated with bitterness in the final product.

Instead of soaking or cooking your beans in vinegar, toss them in a light coating of vinegar just before fermentation.

Don’t Over-ferment Your Tempeh

While fermentation is a nice set-it-and-forget-it method of preparing foods, it’s the most common cause of bitterness in tempeh.

The normal progression of fermentation in tempeh is the development of white fuzzy fibers, then grey patches or spots, then black spots or patches as the spores reach the reproductive stage.

Stopping fermentation when the tempeh is a firm, white cake (again, a bit like a cheese) and refrigerating it can help prevent the development of more bitter flavors.

No two batches of fermentation are exactly the same.

If you love tempeh and plan to make it often, keep an eye on the progress and experiment with stopping fermentation at different times to achieve your preferred flavor.

Taste Test Your Tempeh

If you prefer to buy tempeh rather than make it, every brand has a different flavor and many are more bitter than others.

Try different brands and types to see what you prefer.

Experiment With Different Acids

While vinegar is the most affordable and easily available way to create an acidic environment for your tempeh, it is not the only method.

Experiment with different vinegars or try a different acid altogether, like lemon juice or even wine.

Using sherry vinegar or apple cider vinegar may impart different flavors to your finished tempeh and they are often milder and less bitter than white wine vinegar.

Use Baking Soda to Decrease Bitterness

When preparing finished, cooked, tempeh, consider adding a little bit of baking soda.

Baking soda neutralizes the acids that can promote bitterness, and also improves the browning of foods.

Depending on your recipe and cooking method, baking soda may be easy to add to your cooked tempeh preparation.

However, do not use baking soda while initially making tempeh (as you cook the soybeans, for example) because tempeh requires an acidic environment to ferment.

In Summary

Many people find tempeh to be bitter to the taste, and some brands more than others, because tempeh is made with acidic ingredients.

Steaming tempeh in a steamer basket or in the microwave before cooking it helps to remove bitterness and give it a more neutral flavor.

Depending on your final preparation method or recipe, consider adding a small amount of baking soda to raise the pH and neutralize acidic flavors.

Finally, try different brands and preparation methods to make the tempeh with the flavors you prefer.