So I’ve got a cauldron on the stove going now, with three corned beefs sitting in it. On the package it says to simmer but NOT to boil for three hours. In your opinion, what makes that distinction? Should the water be just sitting there, should an occasional (every 5-10 seconds) bubble be breaking? Faster bubble acceptable? Slower? What’s your mark for simmering-but-not-boiling?
A simmer is, to me, the edge of a boil or a very light boil. So, if you were simmering water it would be at about 99 to 100 degrees C.
The bubbles aren’t breaking. The surface of the water is shimmying, but not tumultuously.
If the water is at simmer, then it’s just about as hot as it can get. Any more heat and you’re just boiling the water away faster. If something has to remain at boiling heat for a couple of hours you don’t want all the water to boil away.
Aside from that the only difference I can see is the mechanical agitation of the water. For example you want pasta to boil, otherwise it’ll clump together. As for simmering meat, a hard boil would be more likely to produce soup or stew rather than cooked meat.
Note that boiling water isn’t any hotter, unless it’s super-heated (and thus not boiling) or if you raise the pressure (e.g. a pressure cooker).
To me, a bare simmer is a bubble every five or ten seconds, a simmer is a bubble or two every second, and a boil, is bubbling everywhere.
I’m not exactly sure about that, but with soup stocks, you don’t want a boil because the agitation of the boil causes the fat to go into suspension and cloud your stock, as well as lending it a greasy mouthfeel.