Brew In a Bag (BIAB)

   
BIAB Basics (Full volume - No Sparge Mashing)
BIAB (Brew in a Bag) is a method of full mash brewing. Less equipment and simple techniques make BIAB the cheapest and easiest way to get into All Grain brewing. Its practically cheating.
How do you go from grain to beer?
There are 4 main steps in turning grain (malt) into beer.
1. Turning the starch in the malt into sugar.
2. Separating the sugary liquid from the grain.
3. Boiling the liquid with hops, then cooling it down.
4. Letting yeast turn the sugar into alcohol and the liquid into beer.
It’s as simple as that. BIAB is a way to complete those 4 steps with a minimum of equipment, complexity and cost.
What will I need to brew a beer using BIAB
1. For a start, you will need all the things that you find in an average home brewing starter kit, like the Coopers home brewery kit. So, a fermentor, airlocks, hydrometer, big spoon, bottles, etc. You won’t be needing the tin of ingredients though !!
2. A great big pot. It will need to be at least 40 litres so you can do an average 20-25 litre batch of beer. It can be stainless or aluminium or shaped like a beer keg with the top cut off it. Doesn’t matter.
3. A gas burner. You can sort of manage it on the top of a kitchen gas stove, but really you are better off with a nice 3 or 4 ring burner from the camping or catering shop for less than $50.00. Some people use electric immersion heaters, but this guide assumes gas.
4. An accurate thermometer. As long as you are sure its accurate in the range from 50 – 80 any waterproof thermometer will do.
5. The Bag. A big bag made out of 100% polyester, very fine mesh. The material most people are using is called Swiss Voile, or maybe just Voile and can be found at stores that sell curtain fabrics (ie: Spotlight, Lincraft, etc.). Less than $10.00 will buy you more than enough for a bag and probably a spare bag as well.
The simplest way to make a decent bag is to sew it like a big pillow case, then sew across the corners to make it a little bit “pointy”. The best BIAB bag is sewn like a big sleeping bag stuff sack. A tube with a round bottom in it. Exactly like your pot. That’s what a BIAB bag is – a lining for your pot.
So How do you do it then?? An example brew with 5kg of grain
   
Work out how much water you need. It will be around this much for a 23 litre batch – 30 + 0.6 x (weight of grain)

• For a 5kg Grain Bill – 33.0 litres. (probably this much would be OK for anything from 4-6kg of grain)

• Put it on the burner to heat up – heat it to 2 degrees C above the temp you want to mash at. Remember to stir thoroughly before you take the temperature.

For a mash temp of 67C heat it to 69C (67C is a nice all round mash temperature that would be appropriate for a wide variety of beers)

 • Put the bag into the pot with the water like it was the liner of a rubbish bin.
• Pour in the crushed grain, stirring well. Try not to splash it too much as too much oxygen can be bad for the brew at this stage.
• Take the temperature after thoroughly stirring for a few minutes.
• If the temperature is too low, turn the burner on low and constantly stir it while you raise the heat to the proper temperature. (67C) It shouldn’t be more than a degree or two off and wont take long. Be careful not to overshoot, its easy to do
• Put a lid on the pot and wrap it up in an old blanket or some towels for insulation. Let it sit for 60 mins.
• Unwrap the pot and put on the burner again. Stirring Constantly – raise the temperature up to 76-78C. Let it rest there for a few  minutes.
• Gather up the bag and lift it out of the pot. If you don’t have a hook or something to hang it off, just hold it over the pot for a few seconds till the liquid isn’t running out very fast, and then heave it in a handy bucket. Hang it off a doorknob or something while it drains out completely.
• Its better if you can arrange for a “skyhook” then you can allow the bag to drain completely while its hanging over the pot
• Try to minimise splashing. But don’t worry about it too much.
• Put the burner on full blast now
From the point where you take the bag out of the pot, the BIAB part is over and you proceed as you would for any other All Grain brew. There are lots of good guides to doing that so they won’t be repeated in any detail here. • Boil the wort and add hops as per your recipe.
• After the boil you can either chill the wort down to the right temperature for pitching the yeast (or you can use a method known as 'No-Chill').
• Leave behind all the hop goo and coagulated proteins when you drain the wort into the fermentor. (or your No-Chill cube)
• Oxygenate the wort, pitch the yeast & ferment yourself some beer !!!