How to brew with a Brew-in-a-Bag System(BIAB)

Brew in a Bag(BIAB ) All-Grain Beer Brewing

In All-Grain brewing there is a new method called Brew-in-a-bag(BIAB).  BIAB originated in Australia and was initially considered controversial.  Many brewers initially believed it produced inferior beer to traditional all-grain brewing methods, however, it is now widely accepted in the homebrew community.  BIAB is an inexpensive way for homebrewers to transition to all grain or partial mash brewing.  Brewers also enjoy brew-in-a-bag for the shorter setup, brewing, and cleanup times.

The concept behind “Brew-In -A-Bag” is to combine the benefits of all grain brewing, such as greater choice of ingredients and more control over flavor, with the minimalism of extract brewing, where everything takes place in a single brew pot.

The BIAB method involves using a grain bag set ing the brew pot to mash the grains, followed by a sparge step where the bag is removed from the pot and the remaining wort is boiled as you would any other beer.  While less efficient than traditional methods, you can easily compensate for this by using a little more grain in the mash.


Brew in a Bag Equipment

For an all grain batch, you need a boil pot(Your batch size plus a few gallons) and ideally a large propane burner to quickly boil it.  For partial mash brewers, a smaller pot (3-4 gallons) is acceptable as you will not be mashing or boiling the full size of you batch.  The brew-in-a-bag method eliminates the need for a mash tun, hot liquor pot, or lauter tun.

The only other equipment you’ll absolutely need, is a bag made of any light weave, strong fabric.  The most economical bag is the one you make yourself.

If you opt to make your own bag,  when selecting a fabric, you should choose a strong one.  By this I mean the it is able to hold 30+ LBS without breaking.  This fabric will act as a filter, holding grains while liquid drains quicklly though it.  A popular material for many brewers is voile. the bag should be sewn together like a pillowcase.  It should be large enough to cover the entire inside of the boil pot, and have a drawstring or tie at the top to allow the bag to be closed.

The bag will line the boil pot and be closed  to hold the grains during the mash.  At the end of the mash the bag is slowly withdrawn and the remaining wort is boiled, cooled, and fermented as any beer would be.

Depending on your equipment setup you might consider getting a false bottom for your boil pot.

Malt near the bottom, that is close to the hot stove, will burn unless steps are taken. Many boil pot manufacturers supply made to measure disks that fit snugly in the bottom of your pot, however, a stainless steel colander works equally well for keeping your grain from burning.

An often cited limitation of brew in a bag is the inability to brew strong beers due to the difficulty of lifting large amounts of grain from the brew pot.  A strong handle will go some way to alleviating this problem.

(Some brewers rig pulleys in order to more easily lift the bag from the pot, but this is beyond the ambitions of most minimalist setups.)


The Process

A quick guide to brew in a bag :

Malt is put into a bag and soaked in water of a pre-determined temperature.

After about an  hour the bag is removed and drained, leaving behind a sugary liquid known as wort.

This is boiled with hops that are added to contribute bitterness, aroma, and taste.  After cooling, the wort is aerated and yeast is added before the wort is fermented for around 2 weeks.

The resulting beer is bottled or kegged.


Final Thoughts

Here are a few more things to consider if you’re trying to use a Brew-In-A-Bag system for yourself :

  • The temperature is hard to control.  Be careful not to overheat the water because it will cool very slowly, and unwanted tannins will be extracted from the malt if it’s too hot.  You can always add more heat if you undershoot.
  • Drops of wort drip everywhere when you remove the bag from the pot.  Put something down to protect your brewing area if you’re worried about making a mess.
  • Because of the relatively unrefined filtering technique, brew-in-a-bag beer can be a bit cloudy, expecially if you wring every last drop of wort out of the grains.  To counter this, add whirlfloc of Irish moss for the last 10 minutes of the boil.
  • The bag can get extremely hot and heavy when full of water so be careful when removing it from the pot.  The bag should be big enough to sit comfortably in the water while leaving enough dry fabric for you to grip.

If you have any questions, leave a reply.  Otherwise, enjoy this brewing technique!





Sources :

“Brew in a Bag”

“Brew in a Bag (BIAB) All Grain Beer Brewing”



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