How To Make 40 Liters (10 Gallons) of Beer.
I was a late starter to homebrewing. Seven years ago I bought a 1-gallon beer making kit. It contained a glass fermenter, thermometer, tubing, racking cane, airlock, cleanser, grains, hops and yeast. All I needed to add was a stock pot, strainer and funnel to get going. Upon tasting my creation after 2 weeks I was hooked!
Today I mainly make just 10 gallon (40 liter) batches of 6% abv IPA (India Pale Ale) for myself and others. And that's because I'm limited to a 70L brewing system I got from China. The ambition is to move to a 3 bbl nano brewing system by year's end and start a commercial nano/micro brewery next year. I can dream, right?
The name of the game now is consistency. My friends would be very disappointed if each new batch tasted different to the IPA they have grown to love (lol). So planning is key. Consistently using the same ingredients and process should get you the same results. Doing this at the home brewing scale can be a bit tricky because of the relatively small volumes concerned and the margin for error.
The day before brewing.
The day before brewing I make a yeast starter from bottom-of-the-kettle wort and bottom-of-the-fermenter yeast I used in the previous batch. Nothing goes to waste. I freeze and thaw out the wort.
It usually has an SG (specific gravity) of around 1.055 so I need to get it down to 1.040 by diluting it... after boiling it and letting it cool down. I then add the yeast and put the 2000 ml Erlenmeyer flask on a magnetic stirrer for at least 24 hours. The yeast multiplies very nicely in this "mini mash" environment.
[So reading between the lines I do not buy yeast or DME]
The next thing I do is measure out all the grains, hops and beer salts. For this size of batch I typically use about 12kg of malt (grain) - about 65% of pale ale base malt, 20% of Vienna malt and the remainder specialty malt.
I use about 500g of three varieties of hops - one bittering hop and two flavoring/aroma hops.
The interesting part is weighing the various salts you need to achieve your desired water chemistry. I'll cover that topic in much more detail in another blog but for now be aware that different types of beer require different ratios of sulfate to chloride to achieve the desired outcome.
I use an online calculator to determine the amount of salts (gypsum, epsom, table salt and calcium chloride) I need for a batch of this type and size.
The last act of the day is to grind the malt with a grain mill.
The purpose of this is to remove the husk and break the kernel (the endosperm) into just enough pieces to extract all the sugar. There is a trade-off. The finer you crush the kernel the better the extraction and efficiency. But the finer you crush the kernel the more "flour" you get as well. Probably another blog post on this as well.
Are we having fun yet? The big day has arrived and we'll be needing all that milled and weighed grain, hops and salts. And water. 70 liters of water. Tap water is usually fine and should ideally be treated with a Campden tablet.
As I mentioned earlier, I use a 70L brewing system. This has an inbuilt controller, pump and heating element.
I use various online calculators to work out the amount of sparge water (another blog post) needed, the expected pre-boil/original/final specific gravity, the expected SRM (beer color), the expected IBU (bitterness) and the expected ABV (final alcohol content).
This is where the starch in the grain gets converted to sugars that the yeast will eventually use to convert to alcohol (and CO2).
First thing is to fill up the brewing system with ample strike water, in my case 50 liters. We then need to heat this up to around 69C (156F) before adding all the milled grain carefully a bit at a time. Make sure you mix up the grain well with a mash paddle to avoid pockets of dry grain.
On my brewing system I can set the program to heat up the water to the desired temperature. Once I'm at 69C (156F), I add the grain and then switch on the circulation pump to circulate the water through the grain. I adjust the flow rate to get a good circulation speed.
The mash normally takes 60 minutes which is approximately the time needed for the enzymes in the grain to convert available starches into sugars. Following this, we lift up the basket with grain in it and allow all the remaining wort (beer) to seep into the brewing kettle. We then sparge (another blog post) with the remaining 20 liters of water we started off with and, again, allow the remaining wort to seep into the kettle. Sparging is just pouring heated water over the grain bed in order to extract as much fermentable sugar as possible into the final wort.
After the mash, we do a boil which typically takes another 60 minutes. The main purpose here is to add hops which will determine the bitterness, flavor and aroma of the final beer.
Adding bittering hops near the start of the boil will add bitterness to the beer and adding aroma/flavor hops near the end of the boil will add flavor and aroma to the beer. The amount and timing of hop addition is the key differentiator between one beer and another even if they use the same hops.
With about 10 minutes to go I add protafloc/whirlfloc which is an extract of carrageenan and other seaweed. It acts to clear suspended particles like haze-forming proteins and other debris in the wort. I also use Springfirm BR-2 which is a balanced complex yeast nutrient whose formula is specifically studied to optimize its effects on yeast growth and yeast survival.
The hop stand (optional).
A popular new technique that I use to get more desired hop aroma and flavor out of my hops is to do a hop stand (also known as whirlpool hopping). This is where you let the temperature of the wort drop to around 80-90C (176-194F) and add hops. This is said to give the hops contact time with the wort at hot-but-not-boiling temperatures which allows a depth of essential oils (and therefore flavor/aroma) to be extracted. I personally start at 90C (176F) and let the temperature free fall for 20 minutes.
Cooling the wort.
At the end of the boil, I recirculate the wort through a plate chiller to cool it down as quickly as possible. Theoretically this is to avoid undesirable off-flavors, such as DMS an diacetyl, from which your beer may never recover and minimize exposure to unnecessary bacteria.
Transferring to the fermenter.
After cooling the wort using the plate chiller I pump the wort directly into the fermenter. It is a good idea to aerate the transferred wort as much as possible before adding the yeast. Fresh yeast love sugar, oxygen and yeast nutrients. Fermentation can take from several days to several weeks or even months depending on the type of beer you are making and the type of yeast you use. I typically let my beer ferment for 5-6 days once I know that fermentation has completely finished.
Another popular technique for getting the absolute most out of your aroma and flavor hops is to "dry hop". This simlply means adding hops to the fermenter just after the peak of fermentation has taken place and before the fermentation ends. This technique is extremely popular for IPAs which is why I use it.
So there you have it. I hope you enjoyed this blog post and learned a little more about homebrewing.