What is the chemistry behind cooked food

Does alcohol evaporate while cooking?

Perhaps you have also wondered whether this old kitchen adage is true: alcohol that is added to the food supposedly evaporates during the cooking process. Especially when children eat, this can lead to heated discussions. This topic is also relevant for people who have to give up alcohol. The bESSERwisser have researched.

Cooks often add the finishing touches to their dishes by adding a little alcohol to them. A shot of wine, whiskey, Madeira or rum are often used in cooking and baking to give a dish even more flavor, character or color. Many gourmets swear by rounding off the taste with alcohol. For many, the risotto only tastes really good with a dash of white wine. For some, the sauce for the steak only develops its full aroma with the added red wine, and cheese fondue tastes best with white wine and cherry brandy. And let's be honest: who doesn't know and love the traditional beer marinade for grilling meat? In order to be able to answer the often discussed question of whether the alcohol remains in the dish after cooking or has already evaporated, one has to understand the chemistry behind this process.

The colloquially known as "alcohol" - also known as ethyl alcohol, spirits or alcohol - is a monohydric alcohol with the chemical formula C2H5OH.

Pure alcohol is colorless and highly flammable, has a burning taste and a characteristically spicy smell.

Ethanol is produced in the production of alcoholic beverages such as beer, wine or spirits through what is known as alcoholic fermentation. In this process, yeasts, i.e. certain mushrooms, convert carbohydrate components such as sugar into ethanol. Ethanol can also be produced by technical synthesis.

Did you know? The boiling point of pure ethanol is 78.32 ° Celsius, which is below that of water. Mixing ethanol with water creates a so-called azeotropic mixture (azeotrope). There are hydrogen bonds between water and ethanol, and these are then in a ratio of 96% (ethanol) to 4% (water). The boiling point of a water-ethanol mixture is slightly below the boiling point of pure ethanol: 78.15 ° C at 1 bar (760mm) and 95.6% alcohol content. At this temperature, water and ethanol evaporate together in a ratio of 96 to 4. Since this also applies to distillation - the thermal separation process for the production of vaporizable liquids - of alcohol, distillation cannot produce pure alcohol, but only 96% strength.

A search for reputable studies looking at the vaporizing of alcohol in cooking did not return many hits. Only a few scientific publications in renowned journals are devoted to this topic and are often cited.

  • In a study from 1992 [1], six different recipes were used to investigate how much alcohol remains in the food during cooking. The following alcoholic beverages were used to prepare the dishes: Burgundy wine, sherry, brandy, creme de cocoa and grand manner. After adding the alcohol, the meal was simmered, flambéed, baked or boiled for different lengths of time, depending on the recipe - from less than a minute to two and a half hours. Then the residual alcohol content in the food was analyzed. The results of the study were as follows: With a short cooking time of less than a minute, around 83 to 85 percent of the added alcohol remained in the food. In the pot roast, which simmered for two and a half hours, alcohol could also be detected, but only 4 to 6 percent of the amount originally added. In the case of baked oysters, 41 to 49 percent of the alcohol was still present after 25 minutes at 191 ° C.
  • In 2011, the residual alcohol content in various dishes was also measured as part of a study [2]. Alcohol was added to a cold fish stew, and after 45 minutes of cooking in a covered pan, it still contained 30 percent of the added alcohol. When preparing a beef and rabbit dish, red wine was added to the food that was already cooking. After boiling for another hour with the lid closed, 5 percent of the added alcohol could still be detected.
  • “Cooking with beer” is the title of a study from 2016 [3] in which the ethanol content in ten different dishes was determined before, during and after preparation. Vinaigrette, pancakes, carrot soup, steamed fish, spare ribs, braised beef as well as porridge, rye bread and wheat bread were tested - the last three also contain alcohol due to fermentation. The authors of the study came to the conclusion that more alcohol than water was lost during preparation and thus the alcohol content in the cooked dishes decreased. One of the authors' main statements was that the cook can influence the residual alcohol content in the food through the cooking time factor - the longer a dish cooks, the more alcohol is lost. It was noteworthy that in some of the fermented dishes a higher alcohol content was measured than theoretically should be contained in it.
  • A 2017 study [4] looked at how alcohol behaves when cooking a liquid dish. Researchers from Denmark added 150 milliliters of beer or wine to 900 milliliters of veal stock and then heated the mixture. Among other things, they were able to show that the concentration of alcohol in food drops faster if a lid is used during cooking. However, this must not be completely closed so that steam can escape. The size of the saucepan used had no influence on the residual alcohol content. In these experiments, too, small amounts of alcohol were still present in the stock after the cooking time.

All the studies cited show that there is definitely residual alcohol in the food, even after long cooking or cooking times. How much that is depends on various factors: Obviously, the alcohol originally used, the amount, but also the method of preparation or whether it was cooked with, without or with the lid open.

To be able to better imagine how much alcohol remains after heating, here is a specific example: You add 100 milliliters of a strong twelve percent wine (and thus 12ml of pure alcohol) to a dish, simmer it for two and a half hours and then divide it into four equal portions. With a residual alcohol content of 4 percent of the originally added alcohol, there would be 0.12 ml of pure alcohol left over in the meal. This corresponds to one milliliter of the original wine and is therefore very little.

The kitchen myth that alcohol evaporates completely when cooking is not true according to the current state of knowledge. Even after prolonged heating, a low concentration of alcohol remains in the food. When it comes to the question of whether the remaining amount of alcohol in the food is problematic or not, it also depends on who is eating. For dry alcoholics, even the slightest amount of alcohol represents the risk of relapse. Pregnant and breastfeeding women, too, are often meticulous about not consuming any alcohol at all. One should keep this in mind when preparing the meal. Here non-alcoholic wine could be an alternative to achieve the taste anyway.

When it comes to the question of whether or not to completely avoid alcohol when cooking for children, opinions are often divided. While some argue that minimal amounts of alcohol cannot harm children, others argue that young people should not be “given a taste”. Children often refuse meals to which alcohol has been added because they do not like the bitter taste. Ultimately, everyone has to decide for themselves whether they want to use alcohol in cooking for the ultimate enjoyment or not.

And what should not be overlooked when discussing alcohol in food: Ethanol is also found in (ripe) fruits and fruit juices as well as in many types of bread or sauerkraut - but only in small quantities. Reason enough for some people who want to strictly avoid alcohol to refrain from it.

 

credentials

[1] Augustin J., Augustin E., Cutrufelli RL et al .: Alcohol retention in food preparation (1992). J Am Diet Assoc. 1992 Apr; 92 (4): 486-8

[2] Mateus D., Ferreira I. and Pinho O .: Headspace SPME – GC / MS evaluation of ethanol retention in cooked meals containing alcoholic drinks (2011). Food Chemistry, Volume 126, Issue 3, 1 June, Pages 1387-1392

[3] Ryapushkina J., Skovenborg E., Astrup A. et al .: Cooking with beer: How much alcohol is left? (2016). International Journal of Gastronomy and Food Science, Volumes 5–6, October – December, Pages 17-26

[4] Snitkjæra P., Ryapushkinaa J. Skovenborg E. et al .: Fate of ethanol during cooking of liquid foods prepared with alcoholic beverages: Theory and experimental studies (2017). Food Chemistry, Volume 230, September 1, Pages 234-240

Article created on 7/10/2018

 

 

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