I made some steel cut oats about 2 weeks a go and put what I did not eat in a Ziploc bag in the fridge (not the freezer). I remembered it today and decided to have it for breakfast. It has a bread like slightly yeasty smell to it that became more pronounced when I cooked it.
I put some sweetener and a bit a half and half on it. It tastes OK on first bite but has the yeasty smell and a tangy aftertaste to it that’s hard to describe. The “tang” is what’s concerning me, I’m guessing there was some slight fermentation going on even in the fridge.
If you like the tang, I soak mine overnight in yogurt whey*. It takes on just the right texture, and I reheat in a double boiler so the probiotics survive.
*I make my own yogurt and strain part of it. Originally for Greek yogurt, but now that’s the by-product of whey.