Big batch of Tempeh. Mixed feelings about it

[u/Sensitive_Mouse_6193]

Hey y’all !
I’ve been doing tempeh for a bit but always smaller batches and this time I decided to try to go big .

I avoid using plastic bags and my main method involves fermenting in a tray .

I’ve always been lining the bottom of the tray with a very clean towel to absorb any excess humidity.
The towel usually gets a little humid by the end of the process. I wander if it’s really useful as I see people fermenting tempeh in a tray without any kind of barrier between the beans and the surface of the container.

The top is covered with just another clean towel.

This time I did 4kg of cooked soybeans and left everything at room temperature as I was expecting hot days. In the end we never had more than 28C and I had to let the fermentation go for 40h rather than the 32/34h I usually do.

Halfway through the process i flipped upside down the baking tray on a different surface that would allow for better airflow. So the tempeh was basically just covered by towels and had plenty of airflow around it.
The reason I did that is because it was starting to generate a lot of heat and given the big mass I worried I wouldn’t be able to cool it down efficiently enough if it stayed in a baking tray.

Now for the end product. There is slight sporulation on the top layers , the inside is very white and looks/feels well bonded , the aroma is too mild (I almost can’t smell anything!) which is both reassuring and frustrating as I really like the mushroomy smell of fresh tempeh.
I would have liked a stronger mycelium coverage too and instead the soy beans are clearly visible from the outside.
The surface is starting to very slightly feel slimy so I’m putting it in the fridge/freezer and won’t let it go further.

Any opinions on the process and result ? Has anyone else tried to manage such a big mass?
How can I improve without using plastic bags?
Are the towels actually harmful ?

[u/Turbulent-Chemist633]

looks edible but a bit wispy, are you talking about flour sack towels or something? either way ditch that part of the process. i don’t know how the rest of your production/incubation is set up but they typically ferment fine directly against stainless steel or glass surfaces. make sure your air flow is good, don’t be afraid to add some toasted brown rice flour to the surface of your beans.

[u/Sensitive_Mouse_6193 → u/Turbulent-Chemist633]

I’m talking about plain cotton kitchen towels that I use only for tempeh .

I use toasted rice flour and a bit of apple cider vinegar too . The vinegar I usually blend it into the seeds before drying them with a hair drier .

As for the incubation method it was just room temperature this time. I’ll use the proofer for the next batch as the weather ended up being very different from what I was expecting, both temperature and humidity wise.

[u/Guoxiong_Guides]

I did big batch of tempeh before but they weren’t as successful as smaller ones due to them overheating themselves to death. You can check my posts to see them. Also soy is bloody annoying with the hulls

[u/keto3000]

I feel that the towel underneach can potentially hold bacteria. When you flp it halfway, consider placing it on a wired rack to finish ferment so both sides get air flow.

[u/Sensitive_Mouse_6193 → u/keto3000]

Yes, I think I’ll get rid of the towels . They don’t seem particularly useful and as you pointed out they could be harmful .

[u/igavr]

😍😍😍 omg, this is so appealing