Steeping Specialty Grains, Whirlpooling, and Darker Beers

Our “Ask the Experts” column poses your brewing questions to industry experts. In this issue’s column, of Beersmith tackles questions about steeping specialty grains, whirlpooling, and adding color to your beer.

What is the right way to steep specialty grains?

Some extract brewers may be unaware that you can introduce off-flavors into your beer by steeping grains at the wrong temperature or with too much water. Specifically, you can get an astringent flavor, which can vary from a slightly bitter flavor to a strong sour flavor akin to sucking on a tea bag. The astringency comes from tannins, which are a polyphenol extracted by grain husks.

Since all beers are made with grains, some tannins exist in every beer. In most cases, the tannins remain below the flavor threshold. However, you can get an excess of tannins by steeping at too high a temperature or with too much water.

To avoid excess tannins, you need to maintain the temperature of your steeped grains below 168°F (76°C). Going higher will leach tannins into your wort. A similar effect occurs if you steep your grains at too high a ph value. Specifically if your water/grain mixture reaches a ph above 6.0, you will leach tannins into the wort.

Most water sources are slightly alkaline in ph. Both surface and ground water sources are alkaline, with a ph above 7.0. The specialty grains you use for steeping are slightly acidic, which means that

they will lower the ph of the wort when you steep your grains. You run into ph problems when you use a large amount of water relative to the amount of grains when steeping.

For example, if we take the simple approach and steep just two pounds (1 kg) of specialty grains in 4 gallons (15 l) of water, it is likely that this small amount of grain will be insufficient to lower the ph below 6.0, and we’ll end up extracting tannins. Conversely, if we limit the water to 2 quarts per pound of grain (4 l/kg), it is highly likely that the specialty grains will have sufficient acidity to reduce the mixture below a ph of 6.0, which will significantly cut down on tannin extraction.

So to summarize, you need to limit both the temperature of the water and the amount of water used when steeping grains. Specifically, I recommend steeping below 168°F (76°C) and using no more than 2 quarts per pound (4 l/kg) of water. I also limit the time of the steep—usually no more than 30 minutes.

How can I best use whirlpool/steeped hops in my homebrew?

Whirlpool hops are primarily used not for bitterness but instead for extracting volatile hops oils. While some hops bitterness is isomerized when the wort is still near boiling temperature, hops utilization falls off quickly once the temperature drops below about 176°F (80°C). A long-boil hops addition is a much better way to add bitterness to your hops if that is your goal.

This brings us back to the hops oils. The four primary hops oils are myrcene, humulene, caryophyllene, and farnesene. The largest of these is myrcene, which makes up 40–60 percent of the hops oils in most varieties. Myrcene has an herbal note that can be described as green, balsamic, or hoppy and can also have piney/citrusy hints as is the case with many American varieties. Cascade, for instance, has a high myrcene content of around 50 percent. Noble hops, in contrast, have low myrcene content.

Humulene is the classic noble hops oil and is widely used in the perfume industry. It has a strong herbal component and has a boiling point just below that of water and

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