There are an abundance of homebrew clone recipes in the homebrewing literature. (We even have a couple on our site. See the links at the bottom of this article.) These purport to give you a recipe that will produce a beer that tastes like the commercial example. But can you really brew a clone brew by following a homebrew clone recipe?
The short answer is that it is highly unlikely. I am not saying this to be needlessly contrarian, nor to disparage the skills of homebrewers. It’s simply is a fact that a clone brew recipe is highly unlikely to produce an exact clone of its intended brew. However, if we carefully examine why this is, we can get on the path to actually brewing a very respectable clone brew – if that’s what we wish — or simply to become better homebrewers who are more aware of the sources of variation in beer.
A Thought Experiment
Let’s start with an imagined scenario. Let’s say that we possess the actual commercial recipe for a famous commercial beer. For the sake of argument, let’s say it’s Sierra Nevada Pale Ale. Let’s further say that we scale this down to a 5.0-gallon (19-L) recipe and arrange a contest in which 100 randomly-chosen homebrewers brew this recipe, and submit it for judging. The judges would include tasting panelists from Sierra Nevada, who regularly assess the commercial brew, and a fresh bottle of the commercial beer would also be entered. The brewers would understand that the point of the contest was to produce a clone. What would the results likely be?
Without actually doing this experiment, we could never know for sure. However, a knowledgable homebrewer with experience at judging contests could make some guesses that would very likely turn out to be true. Here are mine.
I would expect there to be a fair amount of variation within the entries. I would not suspect that the judges would believe they were tasting 101 bottles of Sierra Nevada Pale Ale. I would suspect that at least a majority of the beers would be recognizable as an American style pale ale. I would also suspect, however, that some beers would fall outside that boundary. I would expect that at least a majority of the beers would be “good,” in the sense that they showed no major faults. However, I’d also suspect some would show minor faults and a small minority would be seriously flawed. Among the better beers, I would suspect that some were very solid examples of an American pale ale in general, and that others were additionally very reminiscent of Sierra Nevada in particular. Would any be able to fool the Sierra Nevada panelists? If this were the brewer’s first attempt at brewing the clone, I don’t think so — although I would suspect that a couple entries might come close. If any of the brewers had previously brewed a similar clone recipe, tasted and tweaked it, the odds would go up a bit.
So where would the variation in the finished beers come from? There are many variables that could contribute this, and here are some of the major ones.
Differences in Ingredients
If the brewers were scattered across the country, they would be getting their ingredients from different sources. And, of course, their water profiles would vary (although many would treat their water). If the recipe specified 2-row pale malt and crystal malt (40 °L) for the grain bill, different brewers would get their grains from different maltsters. All 2-row malts do not taste exactly the same, and crystal malts certainly vary from maltster to maltster, even if the color rating is the same. If the brewer made an extract version of the beer, that would be an additional factor that would differ from the commercial beer.
Differences in Equipment
A homebrew clone of Sierra Nevada pale ale would obviously be brewed at a different scale than the commercial example. You would expect that many variables — including how well the mash temperature is maintained, boil vigor, evaporation rate, wort chilling time (and method), etc. — might differ. In addition, some breweries do things that you are not set up to do. For example, it’s fairly common for breweries to have a whirlpool tank — a tank to which the hot wort is pumped after the mash. The wort is held here, whirlpooling (and hence the name of the tank) until many of the solids have dropped out, until it is pumped through the chiller. In addition, differences in extract efficiency and other measures would be expected. And these things would have an effect on the beer.
Differences in Fermentation
In the case of Sierra Nevada, homebrewers have access to the appropriate yeast strain. This is invaluable in producing a quality clone brew. However, in order to produce an exact clone, you would need to know many details of Sierra Nevada’s fermentation profile. For example, you would need to know their pitching rate (rumored to be 0.75 million cells per mL per °Plato, about three-quarters the standard rate given for ale). You would need to know how well oxygenated their wort (in ppm O2) was and what their fermentation temperature was. Pitching rate, wort aeration, and temperature all play a role in the fermentation profile, and especially the production of esters. All three of these work in unison to produce the fermentation profile of the beer. In a clean ale like Sierra Nevada, small differences might not make such a large difference, but if you were cloning a Belgian-style ale with a distinct fermentation profile, they would be very important.
Even if you knew all the relevant variables, you would still be fermenting at a different scale. And differences in fermenter size and fermenter geometry have both been shown to have an effect on beer at the commercial scale. Beyond that, many breweries require two or more batches of wort to fill their fermenter. If a brewery has a 10-bbl brewhouse, but 40-bbl fermenters, they would need to brew 4 times to fill their fermenter, and this would affect the course of fermentation.
Of course, the skill of the brewer also plays a role. However, even in the hands of a talented homebrewer, there are unavoidable differences in beers brewed at a homebrew scale. Some of these could be discovered; for example, you could potentially find the aeration rate of your intended clone brew. Others are unavoidable.
If you stop and think about it for a moment, this situation produces two Catch 22s. The first Catch 22 is that the exact recipe from a commercial brewer is guaranteed not to produce an exact clone brew. This is due to differences in scale, equipment, and procedures. In order to produce an exact clone, you would have to compensate for these differences. This might include tweaks to both the recipe and adjustments to your procedure. In other words an exact homebrew clone brew of Sierra Nevada pale ale could not be made from the same recipe they brew on a commercial scale.
Also, the exact clone recipe — if you hit upon it — would only work for you and your brewery. This brings us to the second Catch 22 — although a clone recipe made from scaling down a commercial recipe is bound to fail (in the sense of not producing an identical beer), it is conversely the best place to start in trying to clone an beer.
There are a lot of homebrew clones published these days. Many are produced from information straight from the brewery. In the hands of a skilled homebrewer, they should produce a nice beer and get you within the ballpark of your intended brew. (And if that’s all you’re shooting for, in most cases a good clone recipe should deliver.) However, to get from something similar to your intended beer to a copy that could fool the brewmaster, you would need brew the beer and taste it side by side with the commercial example. Then, you would need to tweak and rebrew the beer, most likely several times, to start approaching an exact clone.