Simmer, Boil and "Rolling Boil"

Hi All,
It's time to talk food vocabulary again.  I've been asked "What's the difference between a simmer and a boil and what's a rolling or hard boil?".  I might even get into how to "burn water".  Here goes:

When a recipe calls for the food to simmer, it means for the food to continue cooking at a temperature below 212 degrees F.  You will still see bubbles on the surface of the food and occasionally they will pop.  Stirring is still needed because the food is still on the heat source and can burn.  Simmering helps ingredient flavors blend.  This can be an important part of the process and can mean the difference between just OK flavor and very flavorful.  If the recipe calls for the food to simmer, don't skip the process.  It is important to remember because simmer is achieved at a lower temperature; it helps keep foods, herbs and spices from getting scorched.  A scorched food, herb or spice can give off a bitter or bad flavor.  Stirring occasionally also helps prevent scorching.

Water boils at 212 degrees F and we usually associate boiling with water.  We boil water to cook many different things but pasta comes first to my mind.  To boil water, it is best to use a pot or saucepan with a good fitting lid.  The boiling process will occur faster if the pot is covered and remember a watched pot will boil but it will take longer because you are taking the lid off and letting heat escape.  When a food boils, the surface of the food has lots of bubbles and almost all of them pop on the surface.  The rolling boil is the boil when you stir the pot and the boiling doesn't stop.  Remember stirring allows heat to escape and lowers the temperature of the food.  In the time of home canning, foods were boiled to destroy bacteria that may have grown over time.  Many people still follow this logic with foods from the grocery store.  Just remember, high heat can also kill many nutrients.  I'll let you decide which is best for you.

Now let's talk about "burning water".  Of course, you can't burn water but you can let your pot or saucepan cook dry.  What it means is the pan has been on the heat long enough to convert all the liquid to steam and the pan or the solids left in the pan start to burn.  This could result in the loss of a favorite pan or cause a kitchen fire.

I hope this helps clear up the difference between simmer and boil.
Happy Cooking,
Becky Homecy