PSA: I recently brewed a Pale Mexican Lager with Polenta substituted for Flaked Maize. I found the resulting beer to have way more corn flavor than I prefer and a slight astringency (or something harsh). I think the astringency/harness might be (just a guess) from the germ in the polenta.
You want degermed corn products. Not sure if that is the source of the astringency, but the germ has oils that kill the head.
I’m pretty sure any polenta you buy at the store is degerminated for shelf stability.
Flaked corn is easy to work with but I don’t find it has a lot of flavor to it. I don’t know if that’s a function of the way it is partially cooked and then left to sit until it sells or if they select a more bland corn variety. Flaked corn is used mostly to lighten the body of beers rather than produce a strong corn flavor so either could be true.
Bobs Red Mill Polenta has little black specs. They explain on their website those are pieces of germ.
I don’t know if the beer is astringent. It just has a strong corn flavor and some bite that I am not sure about.
I prefer the flaked maize. Just lightening the body and not providing flavor is really what I wanted. I was out and didn’t want to pay shipping for just flaked maize. My experiment failed.
Although, I hear Whole Foods may have corn flakes cereal without additives and sweeteners. I haven’t looked yet.
I’ve never used polenta, but i use a fair amount of flaked corn. At 10% of the grist or less, I don’t get any flavor out of flaked corn. At about 15-20% I start to pick up a cornbread/sweet corn flavor (which I enjoy at a low level in certain lagers).