What is Brew in A Bag?

Brew in a Bag - or you will see it often abbreviated BIAB - is a style of mashing used in homebrewing of beer. The grains that make up the mash bill are placed into a large bag made of porous material that is placed inside the mash kettle (which also doubles as a boil kettle.) When the mash infusion is complete the bag is lifted out of the kettle and left to drain by gravity. Common draining scenarios include suspendeding the grain bag above the kettle and letting it drain back into the kettle or placing the bag in a container to drain and adding the wort back to the kettle. After the drain step, some brewers choose to squeeze the bag to get more wort out. Once the wort is in the kettle brewing continues in the usual way.

The Brew in a Bag style of mashing differs from traditional mashing in that there is no separate container necessary for mashing/sparging and boiling. In addition there are no separate mash and sparge steps employed.

Why Brew in a Bag?

How can BIAB Calculator help me?

Brewing a beer that turns out like your recipe intended involves creating the right amount of wort to put into the fermenter at the right gravity (potential alcohol.) BIAB Calculator allows you to input your exact brewing system parameters so at the end of the brew day you end up with exactly what you want. There are several other mash calculators you could use, but BIAB Calculator focuses on the factors unique to Brew in a Bag to ensure the best possible results.

To ensure results it is highly recommended that you do some tests to get real values for some of the System values in your brewing setup: