Tuesday, January 29, 2013

More Details on High Altitude Baking

Illustration Courtesy of www.cakespy.com
Yesterday I received a GREAT question via email from a reader asking to further explain high altitude baking, so I thought I'd share it along with my answer here.  Hope this helps!

Hi Alaina,

I read your article in the Mexico City Newsletter this last week and can't wait to try the
crunch bars. I love to bake and have found it a bit more of a challenge here. I have been looking for any suggestions on what to do to alter the recipe for high altitude, and I really appreciated your concise list of things to try.

I have been curious as I've been doing some of my own research why the suggestion to increase both the liquid and dry ingredient. Do you know why that is?

I'd love any other baking recipes you try while you are here.

Thank you so much,

The SHORT answer as to why you must increase both liquid and dry ingredients while baking is because all the ingredients you use have important functions within your baked good.  You cannot lump them together into simply "liquid" and "dry" categories becasue each and every ingredient does something different.  Additionally, all of these functions are hindered in different ways at altitude, so you must treat each ingredient individually.

Here is your LONG, more detailed answer, since it seems like you really want to understand this process:

First of all, as you very well know, baking is a complicated, scientific procedure.  There is A LOT going on in that cake pan in the oven!!! But the functions of each produce in your baked good can easily be explained (it's their interactions that are not as easy to explain!), and I also think the effect of high altitude on them can also be explained simply.  Regardless, I still must start from the beginning, becasue I think understanding the principles will help you manipulate your recipes more effectively.

Here are the basic ingredients of baked goods and their functions:
  1. Stabilizers (flour and egg) - lend structure
    • Flour binds and absorbs all other ingredients. Its gluten (from wheat) forms when flour takes up water, and that builds structure.
    • Eggs provide stability because they incorporate/distribute air.  (This also happens to have leavening power, since that air expands when heated.)  Egg yolks will serve to make your baked good a little dryer, while egg whites add moisture and give your baked good volume.
  2. Liquefiers (water/milk, fat, sugar) - loosen/liquefy dough
    • Water/Milk are necessary for flour to form gluten.  They also gelatinize starch (necessary for the cake/baked good to “set”), and dissolve/distribute other ingredients.
    • Fat increases the elasticity of gluten, preventing doughs and batters from being tough and dense.
    • Sugar tightens and bind the dough initially, but because it attracts so much moisture it ultimately tenderizes and loosens the dough in two ways:
      • Sugar takes moisture away from flour, inhibiting gluten development (because, although some gluten is necessary, too much will make your product tough).
      • Sugar also interacts with the starch and delays gelatinization so that the cake can spread and rise before it actually sets.
  3. Leaveners (yeast, baking soda or powder, or steam) - raise, or make lighter
    • Yeast uses warmth, moisture and food (carbs) to ferment (or breathe).  The result is carbon dioxide (which expands to leaven the dough) and alcohol tenderizes the gluten strands.
    • Baking Powder and Soda, although very different, both provide an alkaline (base) ingredient that then interacts with an acid.  These two then combine with liquid and produce carbon dioxide (which expands to leaven the dough).  I can provide you a more detailed description of the chemical leaveners if you like.
    • Steam is produced when air and moisture that was trapped during the mixing process expands.  The three mixing processes that create steam are foaming, creaming and lamination.  Let me know if you want me to explain these processes.
  4. Salt
    • Strengthens gluten strands
    • Contributes to elasticity (improving texture)
    • Flavors
Now, let’s talk about high altitude.  Basically, baked goods cooked at altitude using “sea level” recipes turn out dry and dense.  Why?  The low air pressure at this altitude allows water to boil at a temperature lower than 212°F/100°C, causing the following reactions:
  • Batters/doughs lose moisture quicker, drying out more rapidly.
  • Air bubbles and leavening agents expand faster and at temperatures lower than the temperature needed to “set” the baked good.
  • Protein and starch set and stabilize more slowly because the batter doesn’t get as hot.
With that knowledge, I’ll give you again the suggestions for adapting your recipe to high altitude, and the reasons why:
  1. Increase Baking Temperature - This counteracts the slower protein coagulations and starch gelatinization by providing a higher temperature.
  2. Increase Flour - This helps the structure and stabilizing elements to set at a lower temperature.
  3. Increase Eggs - Also helps the structure and stabilizing elements to set at a lower temperature.
  4. Decrease Sugar - This prevents gelatinization from being delayed too much, preventing the sugar and stabilizing elements from setting.
  5. Decrease Fat - Also prevents gelatinization from being delayed too much, preventing the sugar and stabilizing elements from setting.
  6. Increase Liquids - Compensates for the loss of moisture which occurs at a lower temperature at altitude than it does at sea level.
  7. Decrease Leavener - Counteracts the overexpansion of gas cells which occurs because there is less air pressure and because the temperature required is much lower than is necessary for the baked good to set.
Additionally, your mixing methods might have to change slightly, in order to incorporate slightly less air into your doughs and batters.  Because this air expands more quickly at altitude, your baked goods will expand beautifully with all that air, but then deflate as they cool. 
  1. When creaming butter and sugar together, cream until just combined, not "light and fluffy".
  2. When beating egg whites, beat only until "soft peaks", not "stiff peaks".
Hope this helps you, and everyone else out there!  Remember that baking at altitude is very much variable, so you might have to adjust your recipe a few times before you get it right.  Let me know if you guys have any more questions and Happy Baking!!

Baking & Pastry: Mastering the Art and Craft, 2nd Edition by The Culinary Institute of America
On Food and Cooking by Harold McGee