Brewers Insights – How to read a beer recipe and calculate liquor volumes
Hello, this week we have had many questions form brewers who are making
recipe kits asking about various different parts of the method that appear to
have been missed out, we are going to unlock the answers so you can easily
brew any recipe knowing just the brew length and ingredients listed.
let’s look at a recipe, know I have chosen the Son of Punkie recipe
as although it’s not complicated it is slightly different from the norm in the hop
timings.
There is little point in us adding exact liquor volumes, strike temperatures and
the like as we all have different brewing systems, what will be right for
someone brewing on a Grainfather will not be right for a brew on a three
vessel brewhouse. Giving instructions for these variables is misleading which
is why we don’t do it.
The first thing to look at is the malt bill, on this recipe it is easy, just 5kg of
Maris Otter. It is the weight of the grain bill that is important, as this gives us
our calculation for our mash liquor. As a rule of thumb you will use 2.5 litres of
mash liquor to each kilo of grain. So this gives a mash liquor volume of 12.5
litres.
The instructions say to mash at 66c, hitting somewhere close to this is
important as adjusting either up or down is a bit of a pain. Getting this strike
liquor temperature right is down to trial and error on the brewers part, it’s
about getting to know your system. Type of mash tun here is very important,
plastic tends to pull less heat away from strike water than stainless.
Also the temperature of the grain, perhaps this is likely to be cooler in winter
than summer. My advice is to keep the grain at room temperature over night
before brew day, there will be less variation that way.
Pre heat your mashtun, add a kettle of two of boiling water, pop the lid on and
leave for a good few minutes, before draining. It doesn’t take many brews to
get this temperature nailed but a good starting point is 74c. So we would add
12.5 litres of mash liquor to the 5kg of Maris Otter and this will get us close to
the 66c required.
The mash time is the required rest from adding you liquor to time of draining
or sparging the mash tun, in this case 90 minutes. You can see on this recipe
that it has a mash out temperature and time. If you are brewing on a single
vessel system such as a Grainfather or Brewtools then this is easily done on
the control pannel, if you have a standard mash tun ignore this step.
Next we need to know how much sparge liquor. A couple of points here, the
grain absorbs mash liquor and it’s unlikely that your mash tun is 100%
draining. This is called your dead space, all vessels will likely have it to some
extent and it is best to measure before you start, these volumes can than be
added.
At this point it is best to work backwards, we know the final batch size into the
fermenter is 19 litres, how do we work out the sparge liquor, the amount of
boil off etc. We have calculators on the site that are designed exactly for the
purpose. They allow you to punch in the information that you know, and the
calculators have an educated guess at the values you don’t, and come up
with the results that you require.
You can see here that we have to sparge with about 19 litres to give us a pre
boil volume of about 25 litres. The 6 litres of wort will be lost to evaporation,
kettle dead space and those thirsty hops, these soak up about a litre of wort
per 100g.
Finally, lets look at the hop timings. In a beer recipe hops are timed from the
end of the boil. Here we have Apollo as the first edition at 12 minutes before
the end, it is a 60 minute total boil, add the Apollo hops at when the wort has
been boiling for 48 minutes. You can see that there are others at 5 minutes
before the end.
Take note of hop additions at zero or flame out or steep hops. These are to be
added once the boil has finished and generally steeped in the wort for about
20 minutes.
There is also a dry hop edition, approaches to dry hopping are changing very
rapidly, I would urge brewers to experiment with different methods, however,
traditionally they’re added when fermentation is almost over and in a recipe,
measured in days contact with the wort.
Using this information will allow you to brew any beer recipe as long as you
know the batch size and ingredients.
