Adjunct Grains (Mashing Only)
I devoted a column to these alternative grains in the September 2010 issue (Vol. 31, No. 4), including how to utilize them properly. All of them need to be mashed with a potent base malt since they contain no indigenous diastatic enzyme. If raw, they need to be cooked first (gelatinized); if flaked, they can be put directly into the mash. They are indispensable for some beer styles, such as classic American pils, cream ale, some rye beers and Belgian witbier. They include maize or corn, wheat, rye and oats most commonly, but nearly any starchy grain can be used.
I won’t reiterate the steeping method since it is pretty straightforward, but will offer a few tidbits about steeping malts, especially caramelized malts. Dextrine, crystal or caramel malts are particularly useful for extract brewers since they have such a wide range of colors (3 degrees to 180 degrees Lovibond) and flavor characteristics. They also add body and mouthfeel, and perhaps some fermentable sugars. They are made by warming moist, green malt to mash temperatures before drying, essentially mashing within the husk.
Upon further heating, some of the sugars are caramelized and some are not, the latter often remaining fermentable. Generally, the lower the Lovibond rating, the more likely there are to be some fermentables remaining. As much as 50 percent of the sugars in lighter crystal/caramel malts can be fermented, whereas darker versions may be entirely unfermentable. Essentially, crystal/caramel malts are near impossible to break down further, even in a mash, and are therefore perfect for steeping. Roasted grains will add a ton of color, flavor and aroma, some mouthfeel and zero fermentables.
The advantage of partial-mash brewing is the opportunity to use many of the malts and adjuncts that all-grain brewers can and extract brewers cannot. It also provides an excellent springboard for full all-grain brewing. The one potential caveat, though, is poor grain selection. It is crucial to ensure that the combination of those few pounds of grain will contain the necessary enzymes for complete conversion, generally not an issue with all-grain brewers.
If you are using primarily base malts, then there are no issues, but moving on to kilned malts and adjuncts requires some forethought. Vienna and Munich have enough enzyme to convert themselves, for example, but would not sufficiently convert additional adjunct grains or darker kilned malts.
For perspective, Pilsner and American two-row have 100 degrees to 110 degrees Lintner, while some pale ale malts are as low as 40-60 degrees, making the former roughly twice as effective. Not all base malts are, quite obviously, created equally. The ability of malt to “self-convert” means that if used alone, that malt would convert itself within normal mashing time and temperature. The absolute bottom rating for self-conversion is 35 degrees Lintner. The most potent of all the base malts is American six-row, at about 150 degrees Lintner, meaning that it could convert three to four times its own weight in enzyme-free malt or adjunct. So you can now see how critical the choice of grains is when mashing just 5 pounds or so.
If you are concerned about potential conversion, find the Lintner ratings of your selected malts and see if you will have enough amylase enzyme to complete the job. You can calculate this just like color from Lovibond ratings. Add the degrees Lintner per pound and divide by the number of total pounds of grain and/or malt. If that number is greater than 35 degrees, you will be able to convert. Here’s an example:
You want to make a porter with 5 pounds of adjunct/malt containing Munich malt, chocolate malt, black patent malt and flaked oats. You have ½ pound each of chocolate and black patent, neither of which needs conversion. You also have 1½ pounds of flaked oats and 2 pounds of Munich malt. The Munich malt has all of the conversion power and has a rating of 50 degrees Lintner. That’s 100 Lintner points to convert the 3½ pounds of Munich and flaked oats. That leaves 28.5 degrees Lintner per pound (100 ÷ 3.5 = 28.5), short of the “Rule of 35.”
The solution? Add ½ pound of American six-row (75 degrees Lintner) and you will have absolutely no problem. In fact, it might be wise to keep some six-row, two-row or European pilsner malt handy for mini-mashes to avoid problems. This simple strategy can ensure that your mini-mashes are always a success.
As brewers, we are always looking to improve our beer, though not everyone has the time or facilities to make all-grain. Brewing can be fairly simple or rather complicated, and the information available can be helpful or confusing at times. I like to think of myself as a minimalist brewer, able to sift through the unnecessary and concentrate on the salient. Hopefully, this column will help some of you do the same. Lastly, don’t confuse Lintner and Lovibond!
K. Florian Klemp
K. Florian Klemp is an award-winning homebrewer who thinks there is no more sublime marriage than that of art and science.