Low Temperature vs High Temperature Stocks

Discussion in 'Food & Cooking' started by uberathlete, Mar 23, 2013.

  1. uberathlete

    uberathlete

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    Hi all. Back in the day the common stock making method was low heat and long simmering. But the modern thinking is that a better stock is produced with high heat in a pressure cooker. I was just wondering what people's opinions are on the two methods? What are the differences in the end product? Is one method more suitable than the other in certain applications? Any thoughts on the subject would be appreciated.
     
  2. chefwriter

    chefwriter

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    This is how I understand the reason for pressure cooking of stocks.  The point is not high versus low heat. Water always boils at 212 degrees. The goal is to get the most out of the bones without clouding the stock and not having it take all day. The pressure cooker gets the water to a "boil" but without allowing the roiling boil effect. A rolling boil makes the stock cloudy. So in a pressure cooker the water reaches 212 degrees without disturbing the ingredients and the substances you want are leached out of the bones much quicker without cloudiness. 

    I'm sure someone with a copy of Modernist Cuisine can provide a more scientific explanation.  I'm hoping they do. 
     
  3. petemccracken

    petemccracken

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    Um, water boils at 212°F (100°C) at sea level in an open pan. When you put a lid on, it increases the pressure and the boiling point rises, a minor amount for regular lids, up to something on the order of 250°F (121°C) for a pressure cooker at 1 atmosphere of pressure.

    By controlling the heat, the level of agitation can be controlled to something similar to a simmer, albeit at a much higher temperature.
     
     
  4. siduri

    siduri

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    Yeah, like Pete said.  It's the reason stuff cooks faster in a pressure cooker/img/vbsmilies/smilies/smile.gif

    What i didn;t realize, Pete, is that the reason for simmering slowly is not to have too much agitation?  and the pressure cooker doesn'[t agitate that much? 

    So if that's the case, then, is the agitation a problem because the stock comes out cloudy or does it effect the flavor too? 
     
  5. petemccracken

    petemccracken

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    My guess is the agitation causes the cloudiness, probably from emulsifying the fat(s), but please remember, I'm not an expert in this matter.
     
     
  6. genemachine

    genemachine

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    Hrm. I haven't investigated this in depth, but as a biochemist, my first guess would be cloudiness comes from first dissolved, then coagulated protein. Don't think agitation is that much of a factor. Off to the kitchen/lab/secret underground volcanic lair to do some tests :D
     
  7. scubadoo97

    scubadoo97

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    [​IMG]

    I get pretty clear stock from the PC. And as you can see I'm reducing it and there is agitation but it's been strained prior to reducing
     
  8. siduri

    siduri

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    Ok, but is the flavor or only the aesthetics affected by the cloudiness?  They always make a big deal about not agitating, leaving at a very low temp, with just a bubble every so often, skimming, etc, but what real difference does it make in the flavor?  I can see the importance of the transparency for aesthetic reasons, but if the flavor isn;t affected, then i don't really care for my everyday soup.
     
  9. cheflayne

    cheflayne

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    The flavor profile is affected by boiling as opposed to simmering but the result is not huge. Basically as Pete mentioned, boiling causes some of the fat to be emulsified which rounds out the profile a little bit. A good example of the effect is like when you finish a tomato soup with some butter, it smooths the flavor edges a tad. However, just like I used to tell my people all the time, don't just take my word as gospel, when you have a culinary taste question, sometime do a side by side comparision and form your own opinion. Make two batches, one by boiling, one by simmering, and decide for yourself. My preference is simmering as I feel that the taste of the primary ingredient shines through better.
     
    Last edited: Mar 23, 2013
  10. kokopuffs

    kokopuffs

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    I've always brought my stocks just to the point of beginning to boil when the heat is immediately reduced to a slow simmer.  That method gives me a better flavor IMHO that submitting the mixture to a rolling boil for minutes if no hours.