Bring to a boil, then simmer?

It's the same reason that a cake recipe calls for the oven to be set to a specific temperature -- you want to heat things to a certain temperature for a certain time so that the necessary reactions happen. It's all physics, in the end.

Water boils at 212 F (100 C).  If you have a raging boil, you can bet the temperature at the element/flame is much higher than 212 F and as you reach the surface of the water you approach the boiling point -- so it's hotter at the bottom than the top.  If you have a very mild boil, the temperature is very close to 212 F throughout the fluid.

You bring it to a boil on high heat (first) because you want it to get cooking ASAP, but you leave it to simmer for a given time because you know it'll be cooked by the end of whatever time you've researched.

The instruction, BTABRTAS, tells the cook (s)he may use a lot of heat to bring the pot to temp quickly, and provides a starting point for a "high simmer."  In other words, once the pot is brought to a known 212F, it's not that hard to adjust to the >200F that is the sort of hot simmer you want for reductions and most simmering.   

Patrick's contribution, although well intended, is largely misguided.  For instance, the statement
is untrue.  He can bet whatever he wants, but he'll lose heavily.

BDL

Most home cooks don't know what a simmer is. By coming to a boil first, it's easy to back off to a proper simmer even for most home cooks.

Besides getting up to temperature quickly, what actual cooking advantage is there to first bringing the cooking liquid and ingredients to a boil first and then reducing the temp to the appropriate degree of simmering?  When making a stock, for example, I usually let the water temp come up slowly, and don't bring the water to a boil.  The idea behind that is that the flavors will extract slowly and more flavor will be added to the water or other liquid over the cooking time.  Is this an erroneous assumption?

Schmoozer

Q: Besides getting up to temperature quickly, what actual cooking advantage is there to first bringing the cooking liquid and ingredients to a boil first and then reducing the temp to the appropriate degree of simmering? 

A: Other than speed and allowing you to bump right up against the 'phase change" temp -- nothing.  . 

Q:  When making a stock, for example, I usually let the water temp come up slowly, and don't bring the water to a boil.  The idea behind that is that the flavors will extract slowly and more flavor will be added to the water or other liquid over the cooking time.  Is this an erroneous assumption?

Erroneous?  Pretty much, yes. 

No matter how quickly the stock is brought to temp, it's still going to require long simmering.  However with stock in particular, it's still a good idea to start in cold water, bring the temp up at a controlled rate, and never allow it to boil.  It's not a matter of how much flavor, but which flavors; and a matter of clarity as well. A stock which has been boiled stock will be cloudy and can never be completely clarified. 

BDL

FF,

I'm saying that stock should not be brought to a boil at all. 

Your bones should start in cold water, and be brought at moderate speed to a simmer.  It doesn't need to be super slowly.  Too quick isn't good, though -- you so want to temper the ingredients, not get them hot all at once.  Medium heat to get to the simmer is probably better than low or medium-high.   

The way I was taught, has me holding the aromatics and sachet until after the proto-stock has already had the scum skimmed.  Skim scummed.  Whatever.  So, while the proteins go into cold water, the proteins and aromatics go into water already at the simmer.  I like to simmer stock at just a little less than 200F.  In other words, at around the same temperature as brewing black tea.

With stock in particular, it helps to think of it as being brewed rather than boiled or cooked.

BDL
 

As to braising -- if there's any flour or starch in the braise, boiling makes a difference.  If the braise, like most, includes adding liquid after an initial browning -- boiling helps the deglaze and better incorporates the fond into the liquid. 

Coming from the other side of the question may be both more helpful and practical.  That is, I don't see why you wouldn't BTABRTAS.  It makes it so easy to get the heat right.

BDL

As usual, I agree with BDL and disagree, or the reverse.

You DO want to bring stock very slowly up to temperature -- taking 45 minutes or so for a big pot is good. The reason is that as the proteins in the meat come up in temperature, they coagulate -- this is most of your scum. If you heat very slowly, they will coagulate on the surface of the meat, under the water, and not float free. This means that you can extract their flavor without their clouding the stock. The faster you raise the temperature, the more you are in effect doing a little light stirring, and as (I hope) you know one should not stir stock.

An example: you've got perfectly clear stock simmering. Now reach in and poke a piece of meat. See all the stuff that floats up? That's coagulated protein that's lightly stuck to the surface of the meat. You must now skim that off to keep your stock clear. If you don't poke the meat, you don't have to do this. And if you bring your stock up to temperature very slowly, so that it does not roil significantly, very little scum will float.

I believe that floating scum also becomes bitter because of oxidation, but I'm not positive about that. Certainly it clouds stock, which is enough reason to get rid of it.

Chris,

We don't disagree at all about stock making.  I never boil.  What I do BTABRTAS is braises -- usually.  There are times with braises and stews I would never go past a simmer either.  For instance, not with fish in the pot. 

BDL, Gilbert, Sullivan
Edited by boar_d_laze - 2/22/10 at 8:07am

   Okay, someone has to ask...

   Bdl, Gilbert, Sullivan...please have patience ( ) with me.

   But what is BTABRTAS?

  Bring to a boil, right to a simmer?


  your a funny man

  dan
Edited by gonefishin - 2/22/10 at 12:15pm

 I concur you should never boil stock. When your really need to have a clear stock that you will later use as a base for a consomme boiling the stock will ruin your chances no matter how much you try to clarify your consomme during prepation.

you can also say bring it to a simmer, then simmer...