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If you’ve ever sat down at a pub to a plate of really good fish and chips—the kind in which the fish stays tender and juicy but the crust is supercrisp—odds are that the cook used beer as the main liquid when making the batter. Beer makes such a great base for batter because it simultaneously adds three ingredients—carbon dioxide, foaming agents and alcohol—each of which brings to bear different aspects of physics and chemistry to make the crust light and crisp.
Beer is saturated with CO2. Unlike most solids, like salt and sugar, which dissolve better in hot liquids than they do in cold, gases dissolve more readily at low temperatures. Put beer into a batter mix, and when the batter hits the hot oil, the solubility of the CO2 plummets, and bubbles froth up, expanding the batter mix and lending it a lacy, crisp texture.
That wouldn’t work, of course, if the bubbles burst as soon as they appeared, as happens in a glass of champagne. Instead beer forms a head when poured because it contains foaming agents. Some of these agents are proteins that occur naturally in the beer, and some are ingredients that brewers add to produce a creamy, long-lasting head. These compounds form thin films that surround the bubbles and slow the rate at which they burst.
Foams also make good thermal insulators. When you dunk a piece of beer-battered fish into a deep fryer, most of the heat goes into the batter rather than into the delicate food it encloses. The bubbly batter can heat up to well over 130 degrees Fahrenheit—the point at which so-called Maillard reactions create golden-brown colors and yummy fried flavors—while the fish gently simmers inside.*
The alcohol in the beer also plays an important role in moderating the internal temperature and crisping the crust. Alcohol evaporates faster than water, so a beer batter doesn’t have to cook as long as one made only with water or milk. The faster the batter dries, the lower the risk of overcooking the food. If the chef works fast enough, he can create a beautiful lacework in the coating that yields that classic beer-batter crunch.
*Erratum (2/10/11): The temperature is incorrectly stated as Fahrenheit. It is 130 degrees Celsius.
This article was originally published with the title Beer Batter Is Better.
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12 Comments
Add CommentThat 130 degrees number seems way too low. 310 degrees perhaps?
Reply | Report Abuse | Link to thisYes, this should read 130 degrees Celsius (about 265 degrees Fahrenheit). My apologies for the error.
Reply | Report Abuse | Link to thisI registered just to reply to this article. I just want to say that the use of heading agents is primarily limited to use in large breweries who use a large percentage of corn or rice for fermentables. As a craft brewer I resent the statement that it is a regular practice to add heading agents. A well balanced beer with good base malt and high alpha acid hops will have a nice thick head without using enzymes(most heading agents are derived from pepsin that is derived from pork).
Reply | Report Abuse | Link to thisI enjoyed the remainder of the article and always enjoy a good piece of beer battered halibut.
-A craft brewer from Seattle.
One group of restaurants I avoid are beer-batter ones - there is no worse tasting batter I know of. It interferes with the taste of the fried food, leaves a terrible after taste, and is of an objectionable texture. I advise avoiding it at all costs.
Reply | Report Abuse | Link to thisI love beer battered fish...I haven't got it down pat...but I'm getting there...
Reply | Report Abuse | Link to thisBear in mind that simply because you don't like beer batter, that doesn't mean that others should "avoid it at all costs". You are certainly entitled to your opinion but do not assume that others must follow it.
Reply | Report Abuse | Link to thisBesides, this is Scientific American, and the article did a pretty good job of describing the science of beer batter and what makes it different.
It should actually read 130 Celsius. Degrees are the unit of measure on the Fahrenheit scale. Celsius are the units of measure on the metric scale.
Reply | Report Abuse | Link to thisProperly, "Degrees" should be with used with both Fahrenheit and Celsius scales, since they both use an arbitrary zero. In contrast, the Kelvin scale is absolute (based on absolute zero), and so "Degrees Kelvin" is incorrect.
Reply | Report Abuse | Link to thisJust wanted to correct BeerBrewer on their view that "most heading agents are derived from pepsin which is derived from pork". This is not true. A few big brewers (mostly in the developing, rather than in the developed, world) add propylene glycol alginate as a foam protectant. This is a carbohydrate material derived from seaweed. It's not an animal product, and not an enzyme. Many decades ago some brewers would use pepsin to stabilize their beer clarity but this was superseded in the early 1900s by papain (from paw paw fruit). Nowadays, even papain is seldom used. Fact is that brewing is a pretty clean and transparent industry in terms of its ingredients and processing aids - regardless of whether the brewer is large or small. Yes, there are individual differences, but it all boils down to beer being made by people, and great people make great beer.
Reply | Report Abuse | Link to thisNo one is submitting any recipes. Physics must be empirical!
Reply | Report Abuse | Link to thisAh, I always knew food made with beer was better! I've been making granola and trail mix bars with barley malt and they're great tasting. Barley malt also has a smaller effect on blood glucose than sugar and generally tastes less sweet.
Reply | Report Abuse | Link to thisI posted the trail mix bars recipe here: http://www.madeofgoodfood.com/blog/2011/1/15/easy-healthy-trail-mix-bars.html
"supercrisp" is not an English word. Get some editors, please.
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