A full boil means that you are boiling the full amount of wort—in most cases, 5.5-6 gallons, to allow for boil-off and fermentation waste. Many homebrewers do nothing but a partial boil and have great success. However, you can have a bit more control over many aspects by boiling the full 5 gallons.
You eliminate nearly all risk of bacterial contamination.
There will always be some bacteria present in your beer, but a full boil will greatly reduce any chance that your beer will have any off-flavors. Many water systems have bacteria present, and since you are not topping off your fermenter with unboiled water, you eliminate the chance that this will contaminate your beer.
Better hop utilization.
Since your water to malt extract ratio is much higher, more of the alpha acids are able to be absorbed into the liquid, yielding better utilization.
It is wise to get a full, rolling boil going to get good bitterness from your hops. Also, you'll want to leave the lid off the boil or leave a gap of 1 to 2 inches, so the compounds that cause undesirable flavors and aromas can be boiled off.
Vastly improved color and flavor.
Since your concentration of sugars is much lower, the wort doesn’t caramelize as it does in a partial boil. Caramelization darkens the wort, and has a big effect on the flavor of your beer. Most brewers would agree that a full boil has a biggest impact on the flavor of your beer.
So what kettle should I get?
This depends on a few different factors—are you brewing inside or out? What size batches would you like to brew? Do you think you may eventually expand your love of homebrewing to become an all-grain brewer? At Midwest, we have a brew pot to fill every need from the 20-minute boil extract brewer all the way up to professional grade all-grain setups. Let’s go over what you should consider when shopping for a brew pot.
Will you be brewing inside?
If you’ll be brewing inside, you are somewhat limited as to your choice of kettle. If you try to do a full boil on a ten-gallon batch on your stovetop, all that liquid won’t come to a boil for about 5 hours on high flame, if it comes to a boil at all (Midwest does not recommend brewing on an electric stovetop). Therefore, a full boil on a five-gallon batch is pretty much the limit of what you can do indoors. A homebrewer wanting to do full boils indoors on 5 gallon batches should consider a brew kettle between 7.5 and 10 gallons in capacity.
Will you be brewing outside or in your garage?
If you’ll be brewing outside, that opens up a few more options. Since you can use a propane burner (NEVER use a propane burner indoors!), you won’t be limited as to the size batches you’ll be brewing, up to 45 gallons! This means you can choose any kettle you like, but there are a few other factors to consider, so lets discuss those.
What size batches would you like to brew?
Most homebrewers getting into the hobby start out by making 5-gallon batches. This is because pretty much all of the equipment and recipes are built for that volume. If you want to do larger batches, it should be a multiple of 5. As for extract brewing, you can just double the amount of each ingredient (water, specialty grains, malt extract, hops, and yeast) in any given recipe to make a 10-gallon batch. Likewise, you may triple the amounts for a 15-gallon batch. An extract brewer who loves the hobby will never regret buying one of these bigger kettles. Not only will the ability to perform a full boil greatly improve the overall quality of your beer, but if you ever decide to make the jump to all-grain brewing, your bigger kettle will be able to be used in your new setup, unlike a smaller brew pot.
Think you might like to brew all-grain someday? Maybe tomorrow?
If you’ve been extract brewing for a while and you’ve got 50+ batches under your belt, you may be curious as to what all-grain brewing is all about. Or maybe you’ve already decided to begin building your dream system. A good heavy duty kettle is always a good place to start. And Midwest has lots of cool kettles loaded with features that will make brewing large extract batches easier. But what’s really great about these kettles is that they can be used as a mash tun (extra equipment required) or a hot liquor tank. So even if you buy one to brew extract, you’ll never outgrow it no matter how into the hobby you may get. These kettles all feature a spigot at the bottom of the pot. This is so that you’ll be able to drain the kettle into your fermenter using gravity instead of trying to heft 10 gallons of wort, which we do not recommend! Other features these kettles may have are sight gauges and thermometers. A sight gauge allows you to see how much liquid you have in the kettle. A thermometer will obviously allow you to monitor your temperature while steeping grains, boiling or chilling your wort. When performing an all-grain mash, you must hold the mash at specific temperatures for different parts of the mash. While all these features are quite convenient for the extract brewer, they are absolutely required for the all-grain brewer.
Read more on all-grain brewing here.