BIAB brewing stands for Brew In A Bag brewing method and it is a way to have a full grain brewing day using a single pot for the whole process (hence the name). BIAB is too often being looked down upon by “real” homebrewers who are using the multi-vessel brewing method that includes:
- Making a liquor in a first vessel (hot liquor tank)
- Pouring the liquor into a second container (mash/lauter tank) that is used for grains processing (mashing and lautering)
- The third vessel is called a kettle and is used for boiling the wort
BIAB on the other hand, uses one pot for all three stages and instead of pouring the liquor onto the grain (striking) the grains are submerged into the liquor while in a bag to make the mash and straining out of the mash using that bag. The remaining malt in the pot can then be brought to a boil and become a wort. This is a very simplistic explanation of the BIAB method so I’d like to touch on the process a bit more. If you are not sure what is the basic process of beer making, read John Palmer’s “crash course in Brewing“.
Making the Liquor
The water in the brewing process is extremely important as it will make the most of the final product. The liquor preparation stage has two main parts: getting the right water chemistry and getting the right temperature. The water chemistry depends on the water you use and the beer you are making, each has their own specific water profile needs to make the right flavor. When it comes to BIAB this is really simple: prepare the water just as with any brewing method, just prepare a bit more of it as you will get a big amount of evaporation between the stages.
The second part of the liquor preparation is getting the right temperature: most BIAB recipes go for the simpler solution: a one stage mash with a constant temperature. A good method for BIAB is actually to start on a higher temp and let it cool down slowly. For a multi-stage mash, leave more room for boiling water additions.
Mashing is the heart of the BIAB method: using one pot to do them all. Once the liquor is ready and brought to the right temperature, the mashing needs to begin: preweighing the grains and then adding them slowly to the liquor to avoid any doughing. The mash then sits for 60-90 minutes (depends on the recipe) and the grains are then taken out using the bag and drained. This is a single step mash and it is very straight forward. Many times you will need to correct the mash temperature by introducing some heat: either by adding more boiled water or by heating your pot slightly.
The mash needs to happen according to the standard mashing concept: soaking the grains for a set amount of time in 150-158 F. This temperature is to ensure the extraction of the right amount of fermentable sugars from the grains in the right balance between fermentable and nonfermentable sugars. Using the right pot you can keep the temperature pretty stable through the mashing process, but don’t fuss too much about it: I sometimes add some more boiling water (correct chemistry profile) to the mash if it dips bellow 150 F and the beer turns out just fine.
Once the mashing process is over (60-90 minutes), just take the mash bag with all the grains out of the bag and let it thoroughly drain. At this point, you can choose to let the malt run out or you can “squeeze” it in the bag – there is no conclusive opinion on what is the right way. At some point there was a discussion that squeezed grains will result in a cloudier beer as it has more particulars, I haven’t noticed such result. I always try and squeeze the grains to get as many fermentable sugars out of the grains. As the grains come out hot (150+ F), hang them for a while above a vessel and then give them a good squeeze to get as much thick, sweet malt out of the grains.
The spent grains out of the mash are very rich and full of nutrients, it is recommended to reuse them for some sort feed: dry and grind for bread, used whole as part of any dough or as animal feed (chickens love it).
Since you already have your malt in a pot ready to boiling, just put on a very hot flame and bring it to a boil. Usually, by this point, you have lost about 10-20% of the water and I add another 20% of boiled water to the boiling malt to make for the further evaporation in the wort.
The boiling process then continues just as you would have with any other brewing method, just remember that it is a full grain brew so requires 60 minutes of boil, not less, for a hot break.
A brief (and unclear) history of BIAB
First off, BIAB was never an “official” brewing method and there for is hard to trace its origin: it had evolved as a way to make beer quicker than spending a whole day brewing (as the case with all grain).
Many believe that Australians were the first to some up with the idea, namely a one “Pistol Patch” (Pat) on the AHB (Aussie Home Brewer) forum. In 2006 Pat has published a full post about how to BIAB that had become a very, very long conversation on how to’s of BIAB, worth the read!
Despite that, there are references to BIAB style brewing by Dave Line in his book The Big Book of Brewing from 1974, making it the first real reference to BIAB method, though not in name. Line was a pioneer British homebrewer and so many of the BIAB methods are actually British.
It doesn’t really matter who actually invented the concept of using only one pot for brewing beer, it was the above Pat that made the name to the modern version for the BIAB. for years he fought traditional all-grain homebrewers to prove that BIAB is a valid brewing method and making sure it is on everyone’s radar.
Brew In A Bag is a brilliant, convenient and extremely versatl0ile method to becoming an all grain home brewer. I still think that the move to BIAB, as scary as it was, was the best move for me to making excellent beers. Without the time nor the space for a full all grain setup, BIAB was the right method to brew full controlled high-quality beers.