I've been employing a BIB method for three gallon pilot and experimental batches. After four successful trials (and four pretty tasty experiments
) I thought I'd share it.
The set up accommodates 4-6 lbs of grain and has just enough room for four gallons of water, netting a three gallon yield. Overall I’ve been getting 75-76% efficiency consistently with no sparging of any kind.
Here is the set up. One 5 gallon canning pot, vegetable steamer, five gallon paint strainer bag (washed beforehand) stretched over the pot, all on the typical propane burner (which everyone assumes is for crawfish in my neck of the woods, and what's better with crawfish than beer?). But this could work on a decent stove top as well.
With the brew-in-bag method, all the water: strike, sparge, top off, is placed in the pot and heated to the proper strike temp. I typically round it off to 16 quarts; that leaves just enough space for 4-6 lbs of grain without slopping it all over the place.
With the large volume to grist ration, this is only 3-4 degrees hotter than the target mash temp. I use BeerSmith, set for a 5 gallon brew pot and it pretty well nails it. Doughing in is a snap with all that liquid.
Now we let it mash for a solid hour. I use this sophisticated insulation method. I stir and check the mash temp every fifteen minuets. I will usually add a few seconds of heat 2-3 times in the course of the mash. And I do take the towel off when the burner is on.
The next step I think is critical; a mash out. I heat the grist up to 168 and hold it for five to ten minuets stirring a few times to make sure everything is heated up.
Now comes the “sparge” part. Detach the neck of the bag and lift up the “tea bag”. I will let it drain a minuet or two and dunk it back in. I gently shake it to loosen the grains and get them saturated again, and then lift it out again. I dunk it two or three times, letting it drain to drips after the last dunk. No squeezing is employed.
I set the bag in the lid of the pot, and fish out the vegetable strainer with my charismatic wooden brewing spoon seen earlier, and turn on the flame to start the boil. While it's heating, I’ll press on the bag with the back of the spoon for a second or two to collect another cup or two of liquor out of the bag. I’ll add this to the pot, but again, I do not do any real squeezing.
So now I boil, add hops, cool and pour into the fermentor as normal. My spoon is notched so I know when I’ve gotten down to three gallons. I will adjust the heat and top off as necessary to hit the three gallon mark
You will have a lot more trub than usual, but I have not experienced any problems with it, other than loosing a little more beer than usual when racking. The volume limits the types of beer to mid range gravity beers, employing a single infusion. And you may have to work backwards from the 16 quart or so limit of water and desired gravity to work out your grain bill.
This is pretty good way to get into all grain on a shoestring, and for small and pilot batches. It also shaves a good bit of time off the usual brewday.
Give it a try.