Archives for August 2013

Kitchen measures of weight and volume (in the foreground). may not be as accurate as you’d like. Relatively inexpensive scientific gear can improve your ability measure things accurately. However, even without them, there are ways to reasonably accurately weigh out tiny amounts.

Many homebrew recipes are scaled down from commercial-sized batches. And occasionally you’ll find that the amount of certain ingredients or additives required at the homebrew scale is small, or even tiny. To make matters worst, the ability for homebrewers to accurately measure small weights and volumes is frequently limited. Even scaling a regular, 5.0-gallon (19-L) homebrew recipe down to a 1.0-gallon (3.8-L) test batch sometimes results in certain additions of hops, other spices or mineral salts to be smaller than can be easily measured.

Most cooking-type scales only measure down to 1/4 ounce when set to English units and 5 g when set to metric. (And note that these are close, but not the same. A quarter ounce is 7.1 g.) More accurate scales or balances are available, but they are generally pricey. Along those same lines, measuring small volumes of liquids (for example hop extracts) can be problematic for homebrewers who may have only kitchen measuring cups — or teaspoons and tablespoons — available.

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Getting to a respectable final gravity following a stuck fermentation may be easy, or it can be a real pain.

If your fermentation is stuck, you can sometimes remedy the situation. Depending on the problem, this fix may be fairly simple or more involved. In every case, your first step should be to try to rouse the yeast.

Yeast can flocculate (drop out of solution) suddenly for a variety of reasons, including low temperatures, lack of nutrients or a stressful fermentation. A stressful fermentation frequently results when too few yeast are pitched to a high-gravity wort. Sometimes, however, all it takes is stirring them back into solution to restart the fermentation. This is sometimes called rousing the yeast.

Rousing the Yeast

To rouse your yeast, sanitize a long brewing spoon, racking cane or any utensil that can reach to the bottom of your fermenter. Open the fermenter and stir until the sediment on the bottom is at least temporarily back in solution. Try to stir as quietly as possible, as you don’t want to aerate the wort at this point unless the fermentation stuck before moving more than 1/3 of the way through it’s apparent attenuation range. [For example, if you had an OG 1.080 old ale that you expected to finish at FG 1.020, it would pass through 60 “gravity points” as the beer fermented. If the beer stuck above 1.060 (less than 20 “gravity points” or 1/3 of the way through), aerating it would likely help.]However, aeration after fermentation has started causes diacetyl to form.If you aerate as part of your plan to unstick a fermentation, you’ll have leave the beer on the yeast for a few days, or maybe longer, when fermentation was complete for the diacetyl to be reduced.

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At some point after learning how to brew from grains, most all-grain brewers begin to think about ways to increase their extract efficiency — the amount of extract they obtain from their grain, relative to the maximum possible. (Here, “extract” means carbohydrates and other soluble substances that contribute to the wort’s specific gravity, not malt extract.) Because you can put a number to this, it’s human nature to want improve upon this number. There are several ways to increase your extract efficiency, but often there is a tradeoff.

The Crush

Finely crushed malt yields more extract.

For most homebrewers, getting a better crush is the most effective way to increase their extract efficiency. The more finely malt is crushed, the higher your extract yield. However, finer crushes also lead to lautering problems, as larger husk pieces create a more porous grain bed that allows liquid to flow through with less resistance. In addition, because the husks are reduced to smaller pieces in finer crushes, thereby exhibiting a higher surface to volume ratio, the possibility of extracting an excessive level of tannins is increased.

One approach many homebrewers take is to progressively mill their grain more finely each batch they brew. Once they encounter a problem with lautering, they back off a notch for the next. This trial and error approach works well for finding the best tradeoff between extract efficiency and lauterability on your system.

One way commercial brewers seek to get better efficiency without incurring lautering problems or running the risk of excessive tannin extraction is by conditioning their malt. In malt conditioning, the grain is lightly wetted (usually from steam) immediately prior to milling. This makes the husks slightly more pliable, allowing the brewer to crush the interior of the grain more finely, while leaving larger husk pieces.

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