Cooking is one of the few activities that uses all five senses. Just one other comes to mind, as a matter of fact.
But think about it — the sound of a sizzling pan; the way a medium-rare steak feels when you press it with your thumb; whether the asparagus is bright green or drab; each of these signals conveys information that is as valuable to a cook as the way something tastes or smells.
In many cases, the info being conveyed relates in one way or another to temperature.
Which makes sense, since a major part of cooking is about transforming food through the application of heat.
Indeed, you can learn to judge the temperature of a pot of water just by looking at it. This is a useful skill inasmuch as it allows you to differentiate between poaching and simmering.
What is Simmering?
Simmering is such a common term that you would be forgiven for thinking it's just a synonym for cooking.
But simmering refers to a specific temperature range, and it's a gentle technique that's useful for cooking everything from vegetables, soup and stews, even large cuts of meat.
In the culinary arts, to simmer something means to cook it in liquid with a temperature ranging from 180°F to 205°F.
With simmering you'll see bubbles forming and gently rising to the surface of the water, but the water is not yet at a full rolling boil.
It's the ideal cooking method for making stocks, because it's hot enough to break down the cartilage in the bones, but gentle enough that it doesn't produce large bubbles.
The agitation of a full rolling boil can disrupt the clarification process, leading to a cloudy stock. There's really nothing that needs to be cooked at a full rolling boil. Leave the agitation for the washing machine.
Simmering is also perfect for braising tough cuts of meat. The connective tissues in meat, which make some cuts of meat tough tough and chewy if cooked improperly, are made of a protein called collagen.
But when heated to temperatures between 160° and 205°F, collagen starts to melt and turn into gelatin, which coats the muscle fibers of the meat and causes it to feel moist and succulent.
Boiled meat, on the other hand, becomes tough and stringy, because the higher temperature causes the proteins to denature.
Poaching, by comparison, is a gentler technique, employing temperatures 140°F to 180°F. At this temperature, you may see small bubbles at the bottom of the pot, but no active bubbling. This makes it useful for cooking delicate items like eggs, which would break apart if there was excessive agitation.