How do i know my natto isnt contaminated?

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How do i know my natto isnt contaminated?

Postby ronox on Sat Dec 01, 2018 3:12 am

Hi, long time mushroom grower, deciding to branch out into fermentation since i discovered i love natto, plus most of my mycology supplies are great for sterile fermentation!

Anyway, a little while ago i made 2 attempts to make natto, the first time, i made the mistake of following a guide produced by a moron, who basically cooks their beans inside the pressure cooker (method was to put soaked beans + a specific small amount of water in a steel pot inside the PC that would finish hydrating the beans), because it works for them, they assume theres no excess water and just advise to ferment in the pot (like a pot without a handle sort of thing, like a rice cookers inner bowl).
Anyway, turns out natto doesnt like being saturated with water, i still gave it a taste and it was sour, im assuming thats bad.

Next try, i made everything perfectly, although my container was a tad bit deep, i wasnt aware of the importance of a shallow tray. Once again it turned out sour, though not as sour, it was more like an aroma that you could taste a little.
Im not familiar with what people call "an ammonia smell", since they say the same thing about shark guts, natto, and actual ammonia gas/ammonium hydroxide, all smell incredibly different.

Anyway, this batch i ended up discarding as well, although by looks alone it looked ideal, if a little bit watery.

My issue is, i have no way of knowing what the normal rank fermentation smells of natto should smell like vs potential contaminants. Also, ive learned that theres some balance between ammonia and ammino acids that has to be maintained, in the process of maturing the natto.

Ive encountered one guide which says that ammonia smell is normal but not desirable, and to immediately put the natto in the fridge for a day, afterwards, the flavor improves and the smell dissapears, though others claim their natto is ready from the get go.

I just want to find out what the correct procedure is.

But above all else, i want to know how to tell if my natto is clean or not.
Just to be safe ill be working under a flowhood for my next batch and for the most part treating the sterilized beans as id treat sterilized grains. Ill also be using natto starter spores instead of using beans from the store in case theyve been deliberately or accidentally tained, they arent sealed up after all.
ronox
 
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Re: How do i know my natto isnt contaminated?

Postby cerbu on Sun Dec 02, 2018 5:31 am

in my opinion at above 38 celsius it is next to impossible to contaminate the natto if you keep things fairly clean , no hood needed. I use the spores for good results, now I'm trying new ones https://www.ebay.com/itm/3g-Bag-Bacillu ... %7Ciid%3A1
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Re: How do i know my natto isnt contaminated?

Postby irie1029 on Tue Dec 11, 2018 1:28 pm

my results have never been sour. Mainly the taste is a cross between coffee and unsweet chocolate. The ammonia back taste comes from over-ferment or over temperature. I have had both. Hope this helps.
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Re: How do i know my natto isnt contaminated?

Postby ronox on Sun Dec 23, 2018 8:46 pm

cerbu wrote:in my opinion at above 38 celsius it is next to impossible to contaminate the natto if you keep things fairly clean , no hood needed.


So what your saying is with a standard level of care, so, no major sources of contamination, at over 38C nothing will be able to compete with the natto bacteria?

Sounds like i need to make a new incubator.
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Re: How do i know my natto isnt contaminated?

Postby cerbu on Mon Dec 24, 2018 2:35 am

https://www.aliexpress.com/item/W1401-D ... c32fad1607
this type of inexpensive thermostat is helpful , 38-42 C, the probe near the tray so the beans can spike to 50 on their own , at ~18 hours pull the plug but let the incubator closed to the end , move to cold storage

or this for easier connection
https://www.aliexpress.com/item/LEDSMIT ... 778e82faf6
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