Mechanics of Steeping

To use the caramel and roasted specialty malts, the grain must be crushed to expose the sugars to the water. While the grain is soaking, the hot water is leaching the sugars out of the grain and dissolving them into the wort. The factors that influence how well the sugars are extracted are the steeping time, temperature and the particle size. Obviously, the finer you crush the malt the more completely you can extract the sugars. However, most supply shops have their mills adjusted for mashing and lautering purposes and if the particle size where much smaller, it would be difficult to contain within the grainbag.

Table 10 - Nominal Malt Steeping Yields in Points/Pound/Gallon

Steeping data is experimental and was obtained by steeping 1 lb. in 1 gal at 160°F for 30 minutes. All malts were crushed in a 2 roller mill at the same setting.
* The low extraction from steeping is attributed to unconverted, insoluble starches as revealed by an iodine test.

Steeping specialty grain is like making tea. The crushed grain is soaked in hot 150 - 170°F degree water for 30 minutes. Even though a color change will be noticeable early on, steep for the entire 30 minutes to get as much of the available sugar dissolved into the wort as possible. The grain is removed from the water and that water (now a wort) is then used to dissolve the extract for the boil.

The one sticky part is the phrase, "The grain is removed from the water..." How? Well, the best way is to buy a grain bag. These bags are made of nylon or muslin and have a drawstring closure. They will hold a couple pounds of crushed specialty grain, making in essence a giant tea bag. Most homebrew supply shops have pre-packaged specialty grains in 0.5 - 1 pound amounts for just this purpose.

The analogy to a tea bag is a good one in that if the grain is left in for too long (hours), astringent tannin compounds (a.k.a. phenols) can be extracted from the grain husks. The compounds give the wort a dry puckering taste, much like a black tea that has been left to steep too long. The extraction of tannins is especially prevalent if the water is too hot - above 170°F. Previous practices regarding the use of specialty grains had the brewer putting the grain in the pot and bringing it to a boil before removal. That method often resulted in tannin extraction.

Water chemistry also plays a role in tannin extraction. Steeping the heavily roasted malts in very soft water will produce conditions that are too acidic and harsh flavors will result. Likewise, steeping the lightest crystal malts in hard water could produce conditions that are too alkaline and tannin extraction would be a problem again. In this case, the terms Hard and Soft Water are being used to indicate a high (>200 ppm) or low(<50 ppm) level of carbonates and the degree of alkalinity of the brewing water.

Steeping differs from mashing in that there is no enzyme activity taking place to convert grain or adjunct starches to sugars. Steeping specialty grains is entirely a leaching and dissolution process of sugars into the wort. If grain with enzyme diastatic potential is steeped, that is mashing. See the following chapters for more detail on that process.