Mashing for Kits.
To replace 1 kg of sugar you need to mash about 2.1 Kg of grain. However the exact amount depends on the efficiency of the mash, the type of grain used and how the grain has been crushed.
If you are just replacing the ordinary white sugar that a lot of kits call for use pale malt or lager malt as appropriate. One of the advantages of mashing a little grain for your kit is that you can experiment, your could try brown malt, add a little wheat malt to the mash and improve the beer’s head retention the options are endless.
There are lots of ways to do this I’m going through a simple cheap method and importantly the cost of any hardware you buy is spread across many many batches.
Some crushed grain - 1st choice your local HBS to save postage. If you don't have a local HBS then try The Malt Miller.
A large pan 10 litres or so, 1st choice your kitchen, FreeCycle/Freegle, Car Boot sales or a cheap stainless stock pot from eBay.
A piece of Voile or Net Curtain.
Into your kitchen.
Add 6 liters of tap water to the pan, check the strike temperature calculator and heat to temperature. The mash temperature to aim for is 66°C.
Turn the oven on and bring it to about 66Oc ovens dials aren’t marked accurately so check with your thermometer. Under is better than over as far as temperature goes, all you're trying for is warm.
Get a square of voile and place the grain in the centre, pick the voil up by the corners and you should have something tear drop shape, gather the fabric together and slowly immerse the grain into the warm water. Fold the voile back over the edges of the pan, stir the grain until. the are no lumps and put the lid on the pan.
Put the pan in the oven for 60 mins check the oven temperature from time to time.
Remove the pan from the oven and the lid from the pan, gather the edges of the voile together and slowly lift the grain from the pan. Squeeze as much sweet liquor from the grain back into the pan as you can.
At this point you should have between 3.5 to 4.5 litres in the pan.
Run some warm water into another pan/bucket/bowl and put the grain filled voile into it but without spilling the grain into the water. Fold the voile back over the edges and stir the grain, lift the grain as above and add all the liquid to your pan. You can now dump the grain and rinse the voile.
Bring the pan up to the boil watching carefully as there will be a tendency to boil over, boil for about 1 hr.
Using this in a kit.
Add the contents of the can to the fermenter as usual then add the sweet liquor you have just made topping off as usual with cold water. Stir well and check the SG with a sanitized hydrometer if it’s low yes you can add a little sugar but you're unlikely to need to.
Congratulations you've just done a All Grain Mash by the BIAB method. If you had added hops during the boil you’d have make a batch of All Grain Beer.
Clean up or die!!