I have for years been breakfasting with oatmeal to lower my LDL cholesterol and to lower my risk of colon cancer by increasing my fiber intake. According to my doctor’s office, one needs 5 to 10 grams of soluble fiber a day to lower cholesterol 5%, and I pretty much get that most days. I like oatmeal and, of course, have tried it in my beer. In fact I use a lot of it — close to three-fifths of the grist in my oatmeal pale and brown ales is Avena sativa (oats). I have been able to avoid stuck mashes by using 6-row pale malt for the base. Also, and more importantly, on the advice of Stephan Galente in his BYO article “Oatmeal Stout” from October 1997, I employ a 110–120 ˚F (43–49 °C) beta-glucanase rest before converting starch at 150–160 °F (66–71 °C).
Since lowering my cholesterol is a good thing to do, can I do it with oat beer? With the mash schedule I described, am I brewing beer that has soluble fiber surviving to the bottle? Is the silky texture of my beer due to soluble fiber? Would I even like a beer that has a maximized amount of soluble fiber in it?
I’ve been writing this column for 12 years now and am always surprised by the creativity of homebrewers, especially when it comes to redefining the daily role of beer in one’s life.
Topics of beer and health are unfortunately avoided in the United States and many other countries because of labeling laws and discussions of the beneficial effects of beer consumption are left to medical and health journals that most people do not read.
The wine industry was fortunate when the TV program 60 Minutes aired a segment in 1991 on “The French Paradox.” In Wizard words, this episode addressed the apparent contradiction between a diet high in saturated fat and cholesterol and the relatively low incidence of coronary heart disease in the population eating this diet. The obvious equalizer in this equation was red wine. Ever since, the wine industry has been able to benefit from a topic totally off limits to beer because the French do not drink much beer. Many beers, especially dark and hoppy beers, contain more antioxidants than red wine but brewers have avoided really pursuing this information because of the potential backlash from powerful social groups with strong neo-prohibitionist tendencies. As it turns out, however, the data that was used to point out this paradox apparently underestimated the incidence of coronary heart disease in France and, well, that glass of Cabernet Sauvignon may not really negate the fat in your foie gras after all.
There is a huge body of data supporting the positive affects of foods rich in antioxidants, antioxidant dietary supplements and the consumption of dietary fiber on cardiovascular and GI tract health. So you want to add dietary fiber to your beer and do a little double duty with your double oatmeal stout? Before attempting to answer your question I feel it is important to define dietary fiber and also review the current recommendations on how much fiber you should consume. The American Association of Cereal Chemists (AACC) submitted a report in 2001 that had the following definition for dietary fiber: “Dietary fiber is the edible parts of plants or analogous carbohydrates that are resistant to digestion and absorption in the human small intestine with complete or partial fermentation in the large intestine. Dietary fiber includes polysaccharides, oligosaccharides, lignin and associated plant substances. Dietary fibers promote beneficial physiological effects, including laxation and/or blood cholesterol attenuation and/or blood glucose attenuation.” The recommended daily allowance (RDA) of dietary fiber is 38 grams/day for men age 31–50 and 25 grams/day for women age 31–50.
It is clear from the definition of dietary fiber that you can actually brew a beer that is “fortified” with dietary fiber. Prior to the definition published by the AACC in 2001 this would not be so easy because the definition originally excluded many low and medium molecular weight gums that are soluble in an 80% solution (vol/vol) of ethanol (a test that was part of an older definition). A version of this test using 50% ethanol is useful for determining if there are large molecular weight pectins in wine, cider and fruit beers that may cause filtration problems.
The long and short of the story is that the new definition of dietary fiber includes polysaccharides and oligosaccharides that are not absorbed in the small intestine, regardless of their solubility in a solution of ethanol.
So now let’s go through an estimate of how much dietary fiber you may get in your oat beers containing 60% oats by weight. Most information on the fiber content of oats is based on the assumption that the oats are consumed whole. In the case of brewing the only fiber you get from oats is soluble fiber, a small portion of the total fiber and approximately 5% of the weight of the oats. This is mainly made up of beta-glucan. I estimate that a 20-liter (~5-gallon) batch of beer with 60% oats requires about 2.3 kilograms (5 pounds) of oats. If all of the soluble fiber from the oats is extracted into the wort this translates to about 116 grams of soluble fiber per 20 liters, or about 2 grams per bottle. Since there are inherent inefficiencies in wort production the actual yield will most certainly be lower than 2 grams/bottle. Your use of a beta-glucanase rest is a good way to get as much of the soluble fibers out of the oats and into the wort in your brew kettle, thereby maximizing the yield from the oats.
According to U.S. Food and Drug Administration labeling rules related to this topic, 2 grams per serving is not enough fiber to earn the title “added fiber” to a food label. A boost of at least 2.5 grams per serving (compared to a reference food with no added fiber) is required to use the term “added fiber”. An addition of 2.5–4.9 grams of fiber per serving is considered a “good source” of fiber and 5 grams and more per serving is considered “high fiber.” So far, the oat beer is not looking all that impressive from a fiber per serving perspective.
Let’s look at this from a different angle and ask, how much beer you would need to drink to get the fiber you seek? If you want to get 25% of the RDA of dietary fiber from beer, you may be able to do that if you consume 9.5 grams of fiber per day from your oat brew. Assuming you can get 2 grams per serving, you need to consume 1.6 liters (1.6 quarts) of oat beer, or about five 12-ounce bottles per day. Your ultimate goal is to boost your cardiovascular health, however, and there are plenty of studies that indicate that excessive alcohol consumption has a negative effect on cardiovascular health so you may want to think long and hard before choosing this course of action. Again, oat beer does not appear to be a real fiber powerhouse. You could get close to 5 grams per day by drinking two bottles of oat beer, but that is not much of a contribution to the RDA for dietary fiber.
If you really want to pursue this idea there are ingredients targeted to beverage producers that add dietary fiber to beverages without affecting mouthfeel and flavor. Among these is a product called Fibersol-2 with some sort of maltodextrin as the source of the fiber. According to the marketing literature, fiber-fortified lemonade simply tastes like lemonade. So you could augment the fiber from the oats to a higher level with a fiber additive.
Aside from fiber, oats will give your beer added mouthfeel and I think your description of silky is fitting for the contribution that oats lend to beer. In some styles, such as Belgian wit, oats also contribute a stable cloudiness to beer. In fact, many unfiltered beers get their cloudiness from unmalted wheat and oats and, to a lesser extent, yeast. And finally, if brewers are not as careful as you are with mashing technique and malt selection, oat can cause a headache in the brewhouse.
I am not a nutritionist or dietician, although I did take a few nutrition classes while earning by BS and MS in food science, and encourage readers to consult medical and health professionals for their assessments of health topics. I do have a pretty simple view of diets, however, that is consistent with the advice of many nutritionists and that is to consume a balanced diet based on moderate servings of a variety of foods. You may find that the most pleasurable way to “have your fiber and drink it, too” is to enjoy a beer or two along with a meal that includes some high fiber foods, such as broccoli, cauliflower, spinach, fresh fruits, lentils or brown rice.