To cover or not to cover

[Fat Guy]

It seems that for most dishes there's conventional wisdom about whether or not to cook it covered. In some cases, I can immediately see where the conventional wisdom is supported by tangible improvements in results. For example, if you braise something without a cover on, it's not going to come out very well. It's not really braising if you don't have the cover on. Likewise, try cooking rice without the cover on. That's not going to happen for you.

However, why do we cook pasta uncovered? What about tomato sauce? Most soups?

[Live It Up]

Hmmm...haven't really thought about this one too much. If I am following a recipe, I cook covered or not depending on what is called for. However, for everything else it depends on what I'm going for. I actually employ a partially covered technique for tomato sauce because I want the evaporation that come from simmering uncovered, but I don't want splatters all over my stove. For pasta, I boil uncovered because it boils over if you leave the lid on.

But I am confused when it comes to stock--I've always cooked it uncovered, but then I have to keep adding water to keep the bones covered. Frequently my stock isn't done by the time I go to bed. If I leave it to simmer while I sleep it can boil dry (almost happened with some duck stock I made a few weeks ago). I made some stock a few nights ago and covered it before I went to sleep. When I got up to turn it off, the water level was barely reduced and the stock was done. So, why would you not want to cover a stock?

[markk]

I think it has to do with the fact that things will evaporate uncovered, frequently a desired result when you want flavors to concentrate, or certain ingredients to dry out, balanced by the fact that many things (like things with bones) will "cloud" if you cook them covered, at least while the bones are in there. Those are usually my starting points.

[slkinsey]

Yea, I'm with markk on this one. A lot of these things we cook uncovered we would either like to reduce (e.g., tomato sauce), might suffer from being covered (e.g., stocks), need more attention than a cover can provide (e.g., custard), would like to be at a rolling boil and therefore don't benefit much from a cover (e.g., potatoes), might overboil and foam over (e.g., pasta) and so on. The things we cook covered are only covered because we would like to have a steamy environment and would like to actively discourage evaporation (e.g., rice and braising). Anything that is primarily liquid and will be actively bubbling is not something I would tend to cover as I was cooking it.

I often use some combination of covering and not-covering, primarily for heat-retention purposes. For example, when I cook pasta I always put the lid back on the pasta pot until the water comes back to a full boil.

[alwang]

How do we reconcile the experience from this thread with the conventional wisdom about not covering stocks? I can vouch for the fact that making stock in a pressure cooker makes for a very fine, clear stock.

Edited September 18, 2007 by alwang (log)

[Peter the eater]

Hmmm . . . I will add that I cook pasta covered. I set my electric stove element to a generous albeit arbitrary "six". This is done once there is a good boil and I know from experience the boil will barely be sustained. I feel as though I can save some energy doing this, so why not? There is no detectable difference to my palate with fresh or dry pasta done this way.

[slkinsey]

I wouldn't think that the taste would be different if you cook pasta covered or uncovered. I prefer to cook pasta in the largest volume of water practical (many people cook pasta in far to little water -- I consider 10 quarts to be about minimum for a pound of pasta). As a result, my pasta pot (this one, with a strainer insert) is usually filled close to the top. If I were to leave it covered throughout the pasta cooking process with the burner on full, it would foam over soon after coming back to the boil due to the starch released into the water.

[scubadoo97]

How do we reconcile the experience from this thread with the conventional wisdom about covering stocks?  I can vouch for the fact that making stock in a pressure cooker makes for a very fine, clear stock.

←

Since I've just started using a pressure cooker let me add that under pressure even though the temperature is higher there is less agitation evident by how clean the top is when removed. No splatter. The only thing I see on the lid is condensed steam or water droplets. With stock you should try to avoid the agitation from boiling which will cloud the stock and make it difficult to clear. I have yet to try making stock in the pressure cooker but will attempt it soon. McGee suggest that stock be made uncovered so the top of the liquid is cooler and less likely to boil.

While some sauces can be cooked with or without cover, I am motivated by the mess factor. Tomato sauce cooked uncovered will create a mess all over my cook top and back wall.

Edited September 18, 2007 by scubadoo97 (log)

[russ parsons]

i agree about evaporation. but there is one other thing a lid does: concentrate the heat. saute something uncovered and it browns well on the outside but stays cooler in the center. Cover it and the center will cook more. depends on what you like. I did a chicken saute with peppers last night and cooked it covered in teh beginning to cook the chicken through, then removed the lid to let the sauce reduce a little.

[slkinsey]

Russ, isn't the whole point of the saute technique that you're keeping the ingredients relatively dry? How can that be reconciled with use of a lid?

[scubadoo97]

i agree about evaporation. but there is one other thing a lid does: concentrate the heat. saute something uncovered and it browns well on the outside but stays cooler in the center. Cover it and the center will cook more. depends on what you like. I did a chicken saute with peppers last night and cooked it covered in teh beginning to cook the chicken through, then removed the lid to let the sauce reduce a little.

←

Sometimes when cooking chicken in a pan on the stove I will cook uncovered to brown on one side, flip then cover and reduce the heat if I don't pop it into the oven. The covered pan acts like the oven to help cook the meat through with a more gentle heat.

[russ parsons]

Russ, isn't the whole point of the saute technique that you're keeping the ingredients relatively dry?  How can that be reconciled with use of a lid?

←

depends on what you like Sam, and depends on what you mean by "saute". I'm using the classical definition (well, one classical definition) of a chicken that has been browned and then cooked with other ingredients including a little bit of stock or cream. Obviously, dryness isn't the goal with those. In other "saute" dishes, like a schnitzel, the goal is a crisp skin and in those cases you wouldn't cover.

A lot of this has to do with semantic gray areas: what is the difference between a chicken saute, a fried chicken, a braised chicken and a fricaseed chicken? I'm hoping Michael Ruhlman will be able to make some sense of it with his book and I'm eagerly looking forward to arguing it with him point by point.

[slkinsey]

Ah. So you're talking about "a saute of something," as opposed to the act of sauteing something. I agree that there is usually a moist component in "a something saute" or "saute of something, but I'd argue that the act of sauteing is moving around largely chunk-shaped pieces of food in a limited amount of fat over high heat so as to brown them evenly on all sides (the act of frying being much the same except that the food isn't moved around very much). However, once one has completed the sauteing of the food items one often uses liquid and a lid, and calls the result "something saute." Many times, people are actually frying and call it "saute" for a variety of reasons.

To be more clear, I wasn't reacting to your description of using a lid in your "chicken saute." Rather, I thought I was reacting to your description of using a lid while sauteing. In my understanding, one wouldn't be able to saute (the browning stage of your chicken saute dish) unless the lid was off. The cooking subsequent to the sauteing (or frying) would be braising, if it involved liquid and a lid.

Of course, who knows... Ruhlman may entirely contradict that understanding.

Edited September 18, 2007 by slkinsey (log)

[tim]

How do we reconcile the experience from this thread with the conventional wisdom about covering stocks?  I can vouch for the fact that making stock in a pressure cooker makes for a very fine, clear stock.

←

Since I've just started using a pressure cooker let me add that under pressure even though the temperature is higher there is less agitation evident by how clean the top is when removed. No splatter. The only thing I see on the lid is condensed steam or water droplets. With stock you should try to avoid the agitation from boiling which will cloud the stock and make it difficult to clear. I have yet to try making stock in the pressure cooker but will attempt it soon. McGee suggest that stock be made uncovered so the top of the liquid is cooler and less likely to boil.

While some sauces can be cooked with or without cover, I am motivated by the mess factor. Tomato sauce cooked uncovered will create a mess all over my cook top and back wall.

←

Hi,

Stock made in a pressure cooker does not come to a full boil and there is very little agitation. Once the pressure above the surface of the stock and the pressure on the stock are equalized, there is no agitation and no "boiling", hence a clear stock.

Tim

[annecros]

Interesting topic.

I was raised on an old adage by my thoroughly mean grandmother.

"If it lives above the ground, cook it uncovered. If it lives below the ground, cover it when you cook it."

Not universal, and not my experience, but a reasonable general guide.

[russ parsons]

hmmm, does that mean you cook snake different than chicken?

[melkor]

hmmm, does that mean you cook snake different than chicken?

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Obviously that depends on the snake.

[bdevidal]

I think it has to do with the fact that things will evaporate uncovered, frequently a desired result when you want flavors to concentrate, or certain ingredients to dry out, balanced by the fact that many things (like things with bones) will "cloud" if you cook them covered, at least while the bones are in there.  Those are usually my starting points.

←

It's important to remember, though, that "uncovered to concentrate" will only work with things that have have a higher boiling point/vapor pressure than water, assuming water is the main liquid. So generally yes to solids, no to some liquids and most volatiles. For example, boiling salted water will concentrate the salt, but no amount of boiling of an alcohol+water mixture like beer would concentrate the alcohol. I'm still trying to figure out if I have the guts to run chicken stock through a still...

As far as cloudiness, absent bone taint, that seems to be normally a function of turbulence rather than a direct effect of covering. Uncovered pots have a greater heat gradient (hot bottom, cool top) than covered pots, which makes it much easier to tune the rangetop to a bare simmer. I can do it with a big enough pot, but it is right at the flare-out point on my gas range. That's one reason I really like the oven method. Bring pot up to temp or fill with boiling water, then put in low oven (180-200F). Even heat, low turbulence, unable to boil as the heat never goes over 212F, and dead easy to set. No skimming, no futzing, easy overnight stock

-B

[scubadoo97]

Thanks Tim. Even though I've had a lot of physics and I'm a avid diver it didn't occur to me that without the difference in pressure there would be no boiling but it does now that I think about it.

[NimaCooks]

With sauces, stocks, and other liquids, like others, I have always used the cover as a method of moderating evaporation. Pasta gets cooked lidless to avoid messy foam-overs and tomato sauce gets simmered with the lid partially on to encourage reduction and flavor concentration while limiting splatter on the cooktop.

[Marlene]

How do we reconcile the experience from this thread with the conventional wisdom about not covering stocks?  I can vouch for the fact that making stock in a pressure cooker makes for a very fine, clear stock.

←

I have always covered stocks when simmering.

I cook pasta uncovered for the same reason Sam does, it tends to foam over otherwise.

[fiftydollars]

I think it has to do with the fact that things will evaporate uncovered, frequently a desired result when you want flavors to concentrate, or certain ingredients to dry out, balanced by the fact that many things (like things with bones) will "cloud" if you cook them covered, at least while the bones are in there.  Those are usually my starting points.

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...I'm still trying to figure out if I have the guts to run chicken stock through a still...

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Do it, man!! Do it!!

[birder53]

Water takes longer to boil at 7,000'+. I now keep the pasta pot partly covered to maintain the boil. Sometimes it boils over, but not as a rule. Pasta that cooked in 9 minutes in NJ takes 14 minutes in this part of NM.

[Jmahl]

Someone explain to me the French thing of using parchment paper to cover instead of a solid cover or plate. I don't get it.

Jmahl

[djyee100]

[As far as cloudiness, absent bone taint, that seems to be normally a function of turbulence rather than a direct effect of covering. Uncovered pots have a greater heat gradient (hot bottom, cool top) than covered pots, which makes it much easier to tune the rangetop to a bare simmer. I can do it with a big enough pot, but it is right at the flare-out point on my gas range. That's one reason I really like the oven method. Bring pot up to temp or fill with boiling water, then put in low oven (180-200F). Even heat, low turbulence, unable to boil as the heat never goes over 212F, and dead easy to set. No skimming, no futzing, easy overnight stock

I've found this to be true also. I used to cook stock on the stovetop (uncovered), and did all that dutiful skimming off of scum. I've switched to the oven method, now cook the stock covered during the whole time, and the stock comes out very clear.