I brewed my own beer for the first time today. The process is not difficult. You need to pay attention to time, temperature, volumes and weights but each individual step is very easy. I'll describe the general process alongside the specific process and measurements I followed today. I made a very small batch of stout using a method known as 'brew in a bag'.
Beer is made from water, malted barley (provides fermentable sugars and flavour), hops (bitterness, flavour) and yeast (converts sugars to alcohol).
I bought a kit that contained the grains, hops and yeast to make the stout. It was about 1.2 kg of malt, 17 g of hops and a few grams of yeast. It also advised the water volumes, timings and temperatures to use.
I'd like to try again choosing my own ingredients and come up with my own recipe.
For this method, I used:
The first step is to sterilise the glass jug, the bung, the airlock and the filter.
The second step is to soak the malted barley grains in hot water. The starch in the barley becomes sugar and leeches into the water, along with flavour and colours.
I heated 3.5 L of water to 74 C, then put the grain in the large bag, in the water (looped the drawstring around the thermometer so it didn't get away). Adding the grain drops the heat to around 69 C and it needs to be kept there for 60 minutes. I achieved this by putting the entire saucepan into my oven which I had preheated to just under 70 C. I stirred it 3 times throughout. This mixture of grains and water is called the mash.
I also heated 4.5 L of water to 76 C in the other pot. When the 60 minutes was up, I took the first pot out of the oven, lifted the bag out and put the colander back on top of the pot with the bag in it. I poured the water from the second pot over the bag and colander, then squeezed the excess liquid out of the bag while trying not to burn my fingers.
I moved the colander over to the empty pot, and poured the liquid back over it and squeezed it out. Then did this a third time before removing the bag. I used the spent grains to make bread shortly after.
The resulting liquid is called the wort.
The next step is to boil the wort. This serves two purposes: to sterilise it, and to draw out the bitterness and flavours from the hops.
I brought the wort to a boil then put 7 g of the hops in the smaller drawstring bag and dropped it in. I kept it boiling consistently, adding an additional 10 g to the bag after 40 minutes. I also added something called Whirlfloc after another 10 minutes, then some cacao nibs after a further 5 minutes.
The Whirlfloc is actually Irish moss/carrageen moss - it seems to clump all the floating bits together, keeping them out of the final product. The cacao nibs are just for a slight chocolate flavour.
After 60 minutes total boiling, I took the pot off the heat and put it in the sink with cold water to bring the temperature down, changing the water a few times to speed the process up. I also took a 100 mL sample in the measuring cylinder and measured the specific gravity with a hydrometer - 1.05. You compare this reading to a second reading before bottling to work out the alcohol content.
It is important not to contaminate the wort after it is off the boil - you are preparing a sterile liquid for the yeast to grow in and convert the sugars to alcohol. Other organisms could impact the flavour or compete with the yeast.
Once the wort is cool, you pour it into a container to ferment.
I poured the liquid through a filter funnel into the glass jug up to a 4.75 L mark. I then added the yeast, put the rubber bung in the top of the bottle and thoroughly shook it to mix the yeast through.
Then I put the airlock, half filled with the sanitiser liquid into the bung and left the whole thing in the bottom of a cool cupboard. It will sit there for 2 weeks, bubbling quietly as the yeast makes alcohol.
Not done yet. :)