Brewing Consistently
“Play it again Sam”
This quote is often used, but actually was never said in the film Casablanca (look it up if you don’t believe me). I have used it here because I am going to talk about brewing consistently, which is in part brewing a beer that tastes the same as the beer you last brewed from the same recipe. Many professional brewers will tell you that the biggest weakness homebrewers have is a lack of consistency in their brewing. Of course it is important to them when they are doing the same beer over and over again and it is being widely distributed. A brand will soon lose customers if it doesn’t taste just as they expect it to taste, so pros go to great lengths to ensure that the drinker gets exactly what he expects.
You may say, “So what? I brew for fun and I don’t sell it so I have no need to worry about the same brew turning out differently every time.” In fact, you may say that variations are an important part of the fun of homebrewing. There is something in that argument, and if that is what truly tickles your tonsils, then fine. But suppose you want to make a clone beer, enter a competition, or have a new recipe turn out the way you wanted it to the first time? If you can’t brew one recipe with some consistency then you can’t predict how a new one will turn out. If we take a fairly obvious inconsistency, such as achieving different extract yields when mashing grains, how can you hope to hit target original gravity (OG) in a new brew? And if you don’t do that, you are going to throw it out of balance with other factors such as hop bitterness and the result will be a very different beer from the one you were expecting.
Why do we get variations?
The main reason is that brewing is a complicated process in which many biochemical and chemical reactions occur. These reactions affect the taste of the finished beer and may follow different directions according to the reaction conditions. The brewer has to get them to go in the direction he wants and to manage those reactions (rather than control them). Every step, from selection of ingredients, weighing, mashing, boiling, standing, cooling, yeast pitching and fermentation can cause variations in the finished product. This means that consistency can only be achieved by careful attention to detail during the process. It also means that you should take careful notes throughout the process and standardize procedures based on these notes.
Minimizing variations
Let’s deal with ingredients first, starting with malt. Try not to keep large stocks for long periods, as malt can deteriorate somewhat. This is especially true for base malts (such as pale malt), which have been ground and will easily pick up moisture in storage, becoming “slack” and giving unpredictable extract yields. Grinding is best done no more than a day before brewing to avoid this. If you grind it yourself, check the mill settings each time, and adjust the rollers to a consistent gap. Good retailers will do this for you at a nominal cost, but in that case you should buy only what you need for the brew in hand.
Long storage is not good for malt extracts, either. Opened cans or packs will oxidize and dehydrate so both
flavor and the yield obtained from a given weight will vary. Ideally, limit the amount you buy to that required for a specific brew, and if you have some carryover try to use it in another brew within a week or three. Dried malt extract degrades less in storage than syrup, providing you are scrupulous in keeping it dry. Continuing this theme, “processed” malts such as crystal, caramel, and medium-roasted malts should not be stored for long periods before use because over time they tend to lose many of the desirable flavors that these malts can confer on a beer such as caramel, bready notes and so on.
Mashing grains can lead to significant beer flavor differences if you are not careful. Pay attention to maintaining a constant grain-to-liquid ratio, usually around 1-1¼ qt. water per pound of grain (2.1-2.6 L per kg). And be scrupulous about the temperature of your strike water so you consistently hit target mash temperature; if it is too high your beer may be more malty and full-bodied than you want, if too low then it may be too dry, or even thin. You should also measure the volume of water as accurately as possible, the best way to do this is to calibrate all brewing vessels with a known volume of water and marking the vessel with the measurements. If you can’t mark a vessel, there is always the time-honored route of marking a wooden dip stick as you do the calibration.
You should also know what your extract yield (or brewhouse efficiency) is. You can determine that by checking your gravity against the target gravity for any recipe over a series of brews. At BYO, we work on the basis of a 65% efficiency. If yours is different from that simply use the figure you get and adjust recipes accordingly. Be aware that this may change as your technique improves and adjust grain bills to allow for this. This procedure is analogous to the algorithms so loved by computer programmers, in that it is a loop where you adjust the input on the basis of present data, then adjust again as the end result changes from the value expected. Remember too that your yield will vary according to the amount of sparge water used, so be consistent in this, and try to standardize the sparge volume — calibrate the hot liquor tank as well as the other vessels!
If you are an extract brewer your task will be somewhat easier, since the mashing has been done for you and you have a pretty good idea of what gravity to expect from a given batch of extract. That is, you do if you weigh out the extract carefully, which is not simple with a syrup. If you use a can and accept the weight given for its contents, make sure to rinse it out carefully with hot water so that you get it all into your wort. And if you are repeating a recipe, stick to the same supplier’s product. If you do that and get a good base of data from several brews, then you can change to another product and determine whether it results in any differences. If you are doing a partial mash, then the same strictures apply to that as to grain mashing. Keep the amount of water the same, aim for the same mash temperature, and sparge (rinse) with the same volume of hot liquor.
Naturally, you should adhere to a standard boil time. Make sure it is a vigorous rolling boil and use the same hop variety as in the recipe. But do remember to adjust the weight of hops according to any variation in their alpha acid content if they come from a different batch to that used previously (or quoted in the recipe). And if you use the same batch of hops it should have been kept in the freezer between brews. Then there is the question of cones versus pellets. Some brewers — even one or two large commercial breweries — prefer cones, but they are difficult to sample in a representative manner on a small scale. Pellets, on the other hand, are a much more consistent product and if you use them you can be fairly sure you have the right amount of alpha acid added to the wort.
Late hops added for flavor and aroma should be as fresh as possible. Make sure they are a bright green color (not brown at all). Rub a pellet in your hand and smell them to make sure there are no off odors. If they smell at all cheesy, then it’s best to dump them and use something fresher. Make sure late additions are done at the appropriate times. If you have a stand at the end of the boil keep it to the prescribed duration. Similarly, if you use some form of whirlpool, either by stirring or recirculation, keep the action going for a standard length of time. I recommend conducting the whirlpool very thoroughly as this will aid consistent performance by minimizing wort losses in the trub.
Cooling the wort can introduce some variations, depending upon how you do it and whether your cooling water varies much in temperature from season to season. In this respect, an in-line cooler will give more consistent results that an immersion one, simply because it is more efficient and gives much shorter periods of cooling. And it should be obvious, but at yeast pitching wort temperature should be kept as consistent as possible for similar brews.
Use the same yeast strain as previously; make sure that it is not beyond its use by date and make a starter. Keep the starter wort gravity and volume the same and hold it where ambient temperature does not vary significantly. Just how big of a starter you need will vary according to the type of beer. Most homebrewers under-pitch their yeast, and this is a big source of inconsistency in their beer. When the starter is ready, pitch it into the wort while making sure the latter has been properly aerated, either by thorough stirring and splashing, or by oxygenation using a carbonation stone. Oxygenation is best for the most consistent results, but again, try to standardize the time of oxygenation and the flow-rate of the gas (the latter you will probably have to eyeball).
In the case of fermentation, wide variations of temperature during this process lead to wide variations in beer flavor. If the temperature is too high it can lead to over-production of esters and a lower final gravity (FG) than you want, whereas too cold of a fermentation can result in the FG being too high. You can help this by sticking with a “clean” yeast, such as California Ale, but really you need to control this temperature, especially in the early stages when the yeast is working hardest and is evolving heat. Such control is easy for commercial brewers with jacketed, glycol-cooled fermenters, but it can often be a struggle in homebrewing. I can’t pretend to give easy answers on how to do it, though our ever-inventive homebrewers have come up with ways.
You have to keep the fermenter in an area where the temperature does not vary much, and preferably one where the ambient temperature is close to that desired for fermentation. If you have to ferment in a warm area then try standing the fermenter in cool water, which may need to be frequently changed. Or, use the time-honored method of draping the vessel with a wet towel, which is kept wet until the main yeast action subsides. If the area is too cold then a simple solution is to build an insulated box warmed by an electric lamp. Or if you want to do cool lager fermentations, then use a dedicated refrigerator or freezer with a controller to hold the desired temperature, which is expensive and takes a lot of space. My own solution is to use a conical stainless steel fermenter fitted with a heating/cooling device and a thermostatic controller. These are available from homebrew suppliers, but run into the high hundreds of dollars.
Finale
Space in this column prevents me from getting into bottling/kegging, storage and serving temperatures,
but these are areas that also require attention to detail if you want to achieve consistency. However, if you follow my strictures given above, you will be well on your way to producing beers of consistent high quality. And you do want to be a master brewer, don’t you?
