FAQ: What are the pros & cons of varying kettle sizes?Whether one brews with BIAB or traditionally, all kettle sizes have advantages and disadvantages. For example, a small pot might allow you to use your stove top as a heat source but will only yield a small batch of beer whilst a huge pot might allow you to brew double-batches simply but will be large and heavy to handle, require a strong heat source and single batches might be "shallow" in the kettle leading to high evaporation figures and possibly difficulties with chilling and draining the kettle.
Let’s have a look at three practical options...
Small Pot/Kettle - 30lts (8 US gal)
If you already had a pot of this size, then consider using this for your first few brews. You can still mash a standard 5% ABV beer in this pot but you will need to use considerable top-up water during the boil and also in your fermenter. If your tap water tastes fine, then this need not be a big issue especially when you are just starting out in all-grain. If your tap water is not great, then boil enough for top-up water the night before.
Medium Pot/Kettle – 50lts (13 US gal)
This is a comfortable size kettle with which to brew single batches even those with very high ABV. In some countries, kegs of this size may be bought cheaply which makes this size quite popular but you will still need to keep a close eye on the kettle to avoid boil-overs and double batches in this size pot is stretching the limits – you will need a lot of top up water.
Large Pot/Kettle – 70lts (18.5 US gal)
For those who have decided to purchase a kettle then BIABrewer highly recommends this size. A 70lt pot will give you peace of mind brewing a single batch – no top-up water, very low chance of boil-overs and is still an easy size to handle. It will also allow you to you to brew a double-batch with minimum of discomfort though you will have to watch the pot somewhat and add may have to add a tad of top up water during the boil. This pot is a great all-rounder.
If you have questions regarding this topic, feel free to ask them here.