miso paste pkg instructions: boil your stuff, add the miso, bring back to a boil. Storage: no mention of refrigeration. These are bad instructions, no?
2mon 24d ago by mander.xyz/u/plantteacher in cooking@mander.xyz
When working with miso paste, I normally spread the miso paste over my empty bowl. Then I ensure the soup is well below boiling temp when filling the bowl. This ensures that the probiotics are not killed. That’s my own process. I started doing that after reading similar advice: to add the miso to the pot last, after turning off the heat and letting the temp drop a bit.
For storage, I normally refrigerate the paste after opening. I don’t recall why.. whether it was pkg guidance or just intuition. Some random articles concur (ref 1, ref 2). Ref 1 actually says freezing it is sensible, but probably not good for the probiotics.
I bought a new kind of miso paste (imported from Japan), called “AKA MISO -- Maruman Nama Miso pak”. The suggested recipe on the pkg says to bring the pot to a boil, add the miso, return to the boil, then turn off the heat. So I have to wonder: is the supplier unaware of the health benefits¹ probiotics? Or might there something in the paste that’s risky if not dead?
Along the same lines, there is no mention of refrigeration on the pkg. It just says to consume before the date which is about 1 year out. Does that mean it remains shelf-stable after opening? Or is it just stable enough if it’s cooked to death? I suspect the importer botched the label and forgot to add “refrigerate after opening”.
Ingredients: water, 29% soybean, rice, salt, alcohol. I was surprised at alcohol. Would that kill the probiotics?
¹ Certain gut bacteria is essential for health. But I hear that there is no evidence that probiotic food actually has health benefits. I think someone in c/cooking said that. I’m merely speculating that in the absence of research, probiotics are more likely to bring health benefits than notable risks.
Never boil Miso. Those directions are wrong. It has nothing to do with probiotics. It will denature the enzymes that give it flavor, and end up tasting bitter. 160F or lower is the target
Your initial thoughts on this were correct.
Edit: for the alcohol bit. Alcohol is a normal byproduct of fermentation, but the introduction in miso is a very small amount that won't kill off everything that contributes to the ferment. The salt and minor alcohol content ensure other nasty things don't take hold and grow in the paste, which otherwise would be a great medium for mold or bad bacteria.
Unless you are cooling it down to a really low temperature before adding the miso, any probiotics are killed either way. Like it would probably need to be less than 50°C for anything to survive. To cook something like a chicken breast to be safe to eat, you typically are cooking to a 7 log reduction in bacteria (e.g., only 1 in 10,000,000) survive, and the temperature they are telling you to cook to only needs to be held for 1 second.
Like you said, though, the science around probiotics is still a little unclear. There are a lot of variables to account for. Fermentation of various forms can change the nutrition of a food irrespective of whether you end up eating live cultures. Stomach acid destroys most of what you eat, anyway. I've seen evidence that probiotics help reduce upper respiratory infections, though, so maybe it helps there because it's "upstream" of your stomach.
To actually answer your question, miso, and many fermented products like it, have a high enough salt concentration (and potentially low enough pH), that they are shelf stable. The only reason to keep it refrigerated is to keep the flavor. Alcohol seems to be added as a preservative in a few types of Asian food; i think it might prevent mold growth a bit. Personally the miso i have in my fridge right now has alcohol in it, and it says "keep refrigerated for quality".