Here is a detailed descriptions of how to brew wholegrain beer. The process is similar for brewing beer with a malt extract, just eliminating step 2, which involves creating the wort. See Brewing overview for detailed information on equipment, ingredients and sterilization, as well as links to recipes.
Always start by sterilizing EVERYTHING.
2. Prepare the Wort
Skip this step if you are using a malt extract. However, wholegrain beer is far superior, so I really do recommend taking the time to make your own wort.
Heating the Mash
The goal of heating the mash is to keep the grains submerged in water at around 150F /67C (depending on the recipe) for 60 minutes. This activates the enzymes in the grains so that they convert the complex storage starches into sugars that are easily digested by the yeasts.
The easiest way to get the grains to the right temperature is to heat water on the stove to about 170F / 77C, then add it with the grains to the mash tun. Mix in more boiling water, as needed, until you reach 170F /77C. Then put on the lid and take an hour-long break.
Sparging is the process of completely rinsing the grains to get out all of the wort.
After the mash has rested for 60 minutes, it’s time to drain out the wort. Open the valve at the bottom of the mash tun, and drain all the wort into your boiling pot. (This assumes that your mash tun has a filter. If not, then you will have to follow a complicated process to get the grains to settle out. You can find instructions for Lautering here.)
Heat the sparging water to 170F / 77C (the amount of water will depend on your recipe and how much water you’ve already used). Then pour the hot water through the mash tun, and continue draining the wort into the boiling pot.
Bring the wort to a boil. The wort will boil for about 90 minutes. Through out the 90 minutes you will need to add hops and irish moss according to your recipe. Hops is generally added at several different times throughout the boil because it helps to develop a more complex flavour.
Some people just add the hops right to their boiling pot, but I recommend using a mesh bag so that you don’t have to filter it out later.
4. Chilling Wort
Once the wort has finished boiling, it needs to be chilled to around 70F / 21 C before adding the yeast. Don’t be tempted to to add the yeast earlier or you will end up killing it.
It is also important to chill the wort relatively quickly (it takes me several hours) to prevent wild yeasts and bacteria from colonizing your beer and turning into something funky. The two best ways to do this are with a wort chiller, or by submerging the pot in a bathtub filled with ice.
5. Pitching Yeast
Once the wort has cooled, remove some wort to calculate your original gravity with a hydrometer (only required if you want to know the final alcohol level).
Then add the yeast to chilled wort. Stir the yeast into the wort with the goal of mixing in some oxygen for the yeast.
Be sure to sterilize the yeast package, the mixing spoon and EVERYTHING that touches the beer after this point. (I recommend doing it throughout the brewing process, but it’s more vital after the boiling.)
Using an auto-siphon, move the beer from the boiling pot into carboys with airlocks. Leave lots of head room in your carboys, because the beer will bubble up significantly during the fermentation process.
Store somewhere dark and relatively cool (67F / 19C) for around 10-14 days. It will take that long for the primary fermentation to stop, and you no longer see CO2 bubbles in the airlock.
Adding Hops After Fermentation
If your recipe calls for dry hopping, then you will need to add hops to the beer after fermentation has finished. This final addition of hops is both for flavour and as a preservative, and will result in a deliciously hoppy beer.
Rack the beer using the auto-siphon into a clean carboy. Add in the hops and cap it with an airlock. Allow it sit for another week or two for the hops to dissolve and fall to the bottom.
The beer is fully finished after 2-4 weeks in the carboy, with all of the sugars having been consumed by the yeast. However, it will be flat. So sugar is added before bottling to give the remaining yeasts something to eat, and thus create carbonation in the final bottles of beer.
I recommend racking the beer back into the STERILE boiling pot, leaving behind any remaining sludge in the bottom of the carboys. Then mix dextrose into the whole batch of beer, before bottling.
You can also take your final specific gravity reading at this point (if you want to know the alcohol level).
Beer will build up carbonation, so it needs to be bottled in in plastic bottles, swing-top bottles, or beer bottles that are built to handle the carbonation. If you are doing a large batch of glass bottles, do at least one plastic bottle so that you can test the carbonation by seeing how firm the bottle becomes.
Using the auto-siphon, bottle the beer, leaving about 1.5″ of head room at the top. Cap your beer and store it in a cool, dark location for another 2-4 weeks. The beer is ready when it tastes good!
I recommend drinking homebrew in 3-4 months. Though the beer is shelf-stable, it’s preservative free, and it’s not worth the risk of spoilage.