Dear Mr. Wizard:
I love to drink my husband’s homebrew. But, as with many women, I like to watch my girlish figure. In the March 2001 issue of BYO, I read an article about the use of Beano tablets in the fermenter to lower the carbohydrates. Noticing that I have been having to work a lot harder, watching what I eat and exercising to keep my weight down, my husband decided to try to help me out and make a batch of Beano beer for me. It tastes great as he made my favorite IPA with lots of hops, but I was wondering if this method has been tested to find out if the resulting beer really has a lower content of carbohydrates. The recipe and mash schedule is as follows: 6 lbs. (2.7 kg) pale malt, 0.5 lbs. (0.22 kg) Munich, 0.5 lbs. (0.22 kg) dextrine, 0.25 lbs. (0.11 kg) wheat and crystal malt for color. It was mashed at 140 °F (60 °C) for one hour, then 150 °F (66 °C) for 30 minutes. Four Beano tablets were added to the primary fermenter for a 5 gallon (19 L) batch. I understand that the Munich is as fermentable as the pale malt, but I am wondering how much the crystal, dextrine and wheat might contribute to carbohydrates. Will the Beano tablets take care of this? Please help me, Mr. Wizard! I sure would like to know if this really works.
Deer Island, Oregon
Mr. Wizard respons: Beano Brau . . . now that’s a real blast from the past. I remember reading this article and thought the idea seemed credible, but never gave it a try since I’m not even remotely concerned with my girlish figure!
Before I delve into this question, I want to point out that all types of malt, pale and Munich included, produce wort with both fermentable and unfermentable sugars. It’s the unfermentable sugars that are responsible for beer’s carbohydrate content. Malt type, mashing schedule and yeast strain all influence the carbohydrate content of the beer. Your hubby’s beer had a really solid rest at 140 °F (60 °C) and that really helps when trying to produce a very fermentable wort.
There does appear to be a real demand for low carbohydrate beers these days. Light beer sales are on the increase and new brands continue to emerge. Sam Adams Light and Michelob Ultra are two new brands that come to mind. Just because a beer is low in carbohydrates does not mean that it is prohibited from having flavor. I think that Sam Adams Light is one of the few “light beers” on the market brewed with fuller flavor in mind (mainly hoppiness). Guinness Pub Draught is actually pretty darn low in carbohydrates and alcohol, although Guinness certainly doesn’t want to market its famous stout as “light.” But I digress.
Soon after receiving your question, I decided to conduct “The Beano Challenge.” The experiment was pretty simple and was conducted in a brewpub. Five hundred gallons of wheat wort with an original gravity of 11.25 °Plato (specific gravity 1.045) and 15 IBUs was brewed using the standard brewing procedures for this beer at the brewery where I work. The wort was cooled to 66 °F (18 °C), aerated using sterile air to contain approximately 8 mg oxygen per liter of wort and pitched with White Labs WLP 001 (California Ale) yeast. Primary fermentation lasted 3 days at 66 °F (19 °C) and the gravity after primary was 2.8 °Plato (specific gravity 1.011). We spund or cap our tanks at this point in the process for natural carbonation and this beer was treated no differently. The wheat beer remained at 66 °F (19 °C) for four additional days while carbonation and diacetyl reduction occurred. The gravity had now dropped to 2.0° Plato (specific gravity 1.008) and it was time to cool the tank to 52 °F (11 °C).
Once the beer temperature dropped to 52 °F (11 °C) and stayed at this temperature for 1 day, it was time for the Beano challenge. We took a 0.5 gallon (2 L) sample from the tank for our control sample and a 5 gallon (19 L) sample for our experimental sample. Four Beano tablets were crushed and added to the experimental sample at this point.
Both control and experimental samples were in clear glass containers fit with air locks and held at the same 70 °F (21 °C) for the next 2 weeks. Neither air lock was removed during the 2-week rest. The Beano experimental container slowly bubbled for about 10 days after the Beano tablets were added and there appeared to be a small yeast head on the surface of the beer during this period. The control sample had no yeast head at any time during the test period and rapidly cleared due to yeast flocculation shortly after the sample was taken from the large fermenter.
The results were simple and convincing. The control sample had a final gravity of 1.9° Plato (specific gravity 1.0076); the same final gravity of the large batch of beer in the stainless steel fermenter. This is the normal finish gravity for our unfiltered wheat beer. The experimental sample treated with Beano had a finish gravity of 0.9° Plato (1.0036). This beer has been brewed over 100 times and it has never finished much lower than 1.8° Plato (1.0072). Although this experiment was conducted only once and has absolutely no statistical validity (replicates are required for statistical validation), I’m now a believer in Beano! Long may it rule!
The science behind the action is simple, well-known and used by some commercial brewers to make light beer. The key ingredient in Beano is a debranching enzyme. When added to beer or wort, the debranching enzyme (amyloglucosidase) renders unfermentable sugars into fermentable sugars. Almost all of the carbohydrates found in pale malt, rice and corn can be completely fermented by yeast when amyloglucosidase is added to the mash or fermenation. Some special malts, especially crystal malts, contain “Maillard reaction products” (MRPs). These are colored compounds formed by the reaction of amino acids and carbohydrates. These compounds are not fermentable, are not rendered fermentable by amyloglucosidase and most of the MRPs are not converted to energy when consumed by beer drinkers. The compounds do, however, increase the specific gravity of wort and beer. In other words, your light IPA may not wind up with the same gravity as the same recipe brewed without crystal malt, but the caloric value is most likely the same.
So speaking of caloric value, how does our Beano wheat compare to the regular version? Both beers had the same OG, but the Beano wheat has a higher alcohol content (~5.2% ABV compared to ~4.7% ABV) and a lower carbohydrate content (~4.9 grams versus ~10.3 grams per bottle). I don’t want to get into the specifics of estimating the calories in beer, but my calculations estimate the control beer at 133 calories per 12 ounce (355 mL) serving and the Beano wheat at 122 calories per 12 ounce (355 mL) serving. That’s a reduction in calories of about 8% and a reduction in carbohydrates of 53%. Although the reduction in calories is not huge, it is important to recognize the control beer was fairly lean before the Beano treatment. The 53% reduction in carbohydrate is a bit more substantial. This test is certainly not definitive, but does seem to indicate that Beano does indeed work. I think I will continue tinkering with Beano. My next test will be related to beer farts! I am sure the marketing sharks at the big breweries could have a winning combination if they market a beer-fartless brew that is also low in carbohydrate and calories.