Grocery stores these days offer you more varieties of tempeh than ever before. So you might have noticed that some say that they are pasteurized while others don’t. But what does it mean to pasteurize tempeh? And does this extra production step matter?
Well, we here at Henry’s Tempeh think that it does.
After all, pasteurizing tempeh stops its fermentation. Otherwise, like any other uncooked fermented foods, tempeh will continue to ferment as the mycelia, lactic acid bacteria, and acetobacter (from the vinegar) responsible for the fermentation process continue to grow and flourish. Of course, as William Shurtleff notes in the book on tempeh production, these organisms’ ongoing growth drains the tempeh’s nutrition and healthfulness.
Also, if any bad microbes got onto the tempeh during the fermentation process, they will compete with the good fermenting microbes and eventually outdo them. When that happens it’s not just the quality of the tempeh that suffers, but it becomes downright dangerous to eat. These are the reasons why, if you’ve seen unpasteurized tempeh out there in the wild, its shelf life was likely much shorter than pasteurized varieties.
So then pasteurization is good because it extends your tempeh’s shelf-life.
Having something stay good for a few months instead of a few days is a great boon for shipping tempeh around and for stocking up during sales. But you might have also noticed that some unpasteurized tempeh still has a pretty lengthy shelf-life. This is because they are frozen. What’s up with that?
Well, it’s true that chilling fermented foods helps them last longer. And the colder these foods get the slower the ongoing fermentation becomes. Just like how an open jar of unpasteurized sauerkraut can keep in the fridge for a few months (as long as you keep the kraut under the brine (as per Wildbrine’s advice)), frozen tempeh can live a lengthy shelf-life.
As long as it is kept frozen.
But if it’s that simple, why pasteurize at all? Well, as Alison at Stay Healthy Hacks notes, freezing and thawing a food changes its water content and this change can affect its texture and taste. More importantly, however, freezing tempeh only slows down fermentation, it does not stop it.
To guarantee that your tempeh is safe to eat it needs to be cooked to an internal temperature of 75°C for at least 60 seconds. This temperature and length of time means that the growth of any other microbe that might be on the tempeh has been cut off and most anything harmful will be killed. Great! Unfortunately that means that the probiotics that you might have heard tempeh touted for are also killed. Though there is some research from the International Journal of Molecular Sciences (available via the National Library of Medicine) that suggests that even dead probiotics can be helpful for our gut health. So not all may be lost if you’re hoping to give your gut microbiome a boost.
We here at Henry’s Tempeh pasteurize our tempeh for food safety and shelf-life reasons, but also because it is central to our process. Also, thanks to this pasteurizing step and not fermenting with bags, we are able to limit our plastic use. We only introduce our tempeh to plastic once it’s been fast-chilled down to 4°C after it’s been hand-cut.
In the end, the choice between pasteurized or unpasteurized tempeh comes down to personal preference. And no matter how your tempeh is made there is one simple step you can add to most of your tempeh recipes to practically guarantee that it’s tasty every time.