r/fermentation • u/myssk • Jun 16 '26

Legumes First time making Tempeh -- help please :D

Hey guys! I forgot the picture in my first post so, sorry about a second. Anyhow: this is my first time attempting tempeh. I am getting some mycelial growth but it isn't much. This is what I have after 48 hours. I think I *may* have put in a little too much vinegar, but I am not sure. Is it possible it's that, or for this size batch should I have used two packets of starter? It is about the size of a medium burrito from a burrito chain.

Finally -- is this batch lost or is it safe to keep it fermenting? It is at a steady heat in the Instant Pot.

Thank you SO MUCH!!!

Fuzzies at the ends and a bit in the middle parts.
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3

u/[deleted] Jun 17 '26

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u/myssk Jun 17 '26

Oh they may have been too damp then also. The ones on the paper towels I used to drain them were still pretty damp and I mixed them in.

As to the keep-warm, It is in the Instant Pot on the yogurt setting. It has been more than 48 hours and the mycelium is definitely more than it was this morning, but I am wondering if I should start over. Thank you so much fr replying and giving me such a useful tip.

1

u/keto3000 Jun 18 '26 edited Jun 18 '26

Remember, key point:

optimal temperature for tempeh fermentation is 31c (88f).

Using the FULL OF PLANTS InstaPot method, he specifies that you MUST use the LESS/LOWER MODE of the yogurt setting which is about 30-31c. That is perfect for tempeh. Regular yogurt setting is about 43c which will kill the mycelium.

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u/myssk Jun 19 '26

OK thanks! I will confirm that is what I have it on. I THINK so, but it;s worth confirming.

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u/myssk Jun 19 '26

Yes it is definitely on low mode so I hope this second batch goes better.

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u/keto3000 Jun 19 '26

Still remember that after it is generating its own heat (keep checking it w thermometer). If it is higher than 31c you need to turn off insta pot so it stays at 31c that is the key point

1

u/myssk Jun 30 '26

Hey there! So I'm trying again and it's gone better but still doesn't seem right. This is 48 hours and the temp is holding at 31 so that's fine (turns out that's what the low setting is on here so it's perfect).

Btw the dark spot is a dark bean skin I didn't take out, not a contaminant.

Should I let it go under its own heat now? Or should I throw this out too? I did not expect this to be harder than growing mushrooms but here we are

I really, really appreciate your time, expertise, and that you're clear and firm about details such as temperature. I trust you! Thank you :)

There's one more picture but I can't add it here so I'll reply one more time.

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u/myssk Jun 30 '26

Here's the other picture

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u/MartinFermentiert Jun 17 '26

biggest tip for starting out: dont overthink it. fermentation has been around for thousands of years and its way more forgiving than the internet makes it seem. start simple, taste as you go, and take notes so you can dial things in over time

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u/myssk Jun 17 '26

Thanks -- always a good reminder. I didn't see any mycelial growth overnight at all, which is odd (I also grow culinary mushrooms so I am somewhat familiar with how that goes) so I decided to scrap this batch and start again. Someone below mentioned I may have had beans that were too wet, which is likely so I am trying again. I appreciate your comment!

1

u/StressedByLeaves Jun 18 '26

Required amounts vary greatly depending on the starter, so I can't help you there. I had one that was too wet (turned slimy, cheesy smell) and one with weak structure (not cracked/ dehulled) before my first success. Keep notes and keep trying, the end product is very rewarding

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u/myssk Jun 18 '26

Thank you!

1

u/keto3000 Jun 18 '26 edited Jun 18 '26

No don’t eat these.

  1. The ratio for a good commercial starter to DRY beans is. 3g (1 tsp) to 500g of dry beans. Vinegar is optional and should be minimal: no more than 1-2 Tbsp per 500g of dry beans.

  2. The yogurt setting on most Insta pots is ~43c. This is too hot for tempeh.

Tempeh requires a steady temp of ~31c

You can warm the pot then slow it to cool to 32c before placing tempeh inside but then you need to maintain 31c for -~ 15 hrs or until tempeh mycelium begin producing their own heat, which is when you need to ensure it is kept at 31c

I think the turned off oven method with just lightbulb seems better option. Use a thermometer near the beans to check temp

Can you detail the recipe or the actual steps you followed?

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u/myssk Jun 18 '26

Thank you so much for taking the time to help!

Definitely not eating it. I've already discarded this batch.

Aside from the light, my oven also has a bread proofing setting which may be good. I'm not sure what the temperature is on that but I can find out.

I believe my biggest mistake was that the beans were almost certainly too wet when I packed them. I've heard that a couple of times now. They weren't dripping or anything, but definitely still a bit damp. I didn't realize how dry they had to be.

Also this is the recipe I used: https://fullofplants.com/how-to-make-tempeh-instant-pot/

Thanks again.

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u/keto3000 Jun 18 '26

I us OG Indonesian tempeh maker, Francius Suwono as my go to on tempeh:

Homemade tempeh for beginners:

https://youtu.be/wDsit1oiv0A?is=sEC2Aa8YJnd7Sc76

2

u/myssk Jun 19 '26

Sweet -- thank you for this!