harr.. Paint strainer for BIAB

I thought I could use a "5 gallon paint stainer bag" as a bag for BIAB... but to my great surprise, 5 gallon is not the size of the bag! The bag is smaller.. it's like the half of the size of a carboy (so 2-3 gallon).

I suppose I'm on my own to make a diy BIAB grain bag out of a piece of curtain.

I think I read that the "large" bags from Brewmaasters warehouse are pretty large? YMMV

how big is your batch? i just used the 5 gal paint strainer bag from home depot for a 5.5 gallon batch with 13 lbs of grain.

i just used one of these for a 3 gal batch with 6 lbs of grain and it fit easily.

I was aiming at a 2.5g batch and I heard that you need twice the volume cooking pot for when the grain is inserted. Also the bag has to be big enough to fill the whole cooking pot. So that leaves me to make a 1 gallon batch with my paint strainer

Not really, the bag you have should work out just fine for 2.5 gallons. My VLGB is about 5 gallons, but I've used it without any problem in an 60-quart kettle.

If I'm brewing smaller batches that would only require a couple lbs of grain, is there any reason a strainer bag that is large enough to hold the grain but not large enough to stretch around the pot wouldnt work? Meaning I would have use it more like steeping, I can see it would make stirring the grain difficult but is there anything I'm missing?

I use 5 gal paint strainer bags all the time from lining my 5 gal igloo mlt to using them as hop bags. They work for everything. Are you sure you got the right size? I've had 12 lbs of grain in one before.

You got the wrong size. Those bags are made to line the inside of a 5-gallon paint bucket. I use them all the time and they are F*CKING AWESOME.

the 5G paint strainer bag i got at LOWES fit nicely over my 5 and 7 1/2 gallon kettles.

whats the best way to improve efficiency using this method. i brewed like this and got OG 1.040 when it was supposed to be around 1.055. Mashed for 90 minutes at 152 and single sparged at 170. I know I didn't boil off enough water (about 1/2 gallon left in the kettle) but that shouldn't account for that much of a miss.

this is my grain bill:
5 lb American Two Row
1 lb Crystal 10

will the crystal 10 not convert as much, thus accounting for the large miss since 16% of the grain bill is crystal. 5 lbs of American 2 Row should yield 1.040 for a 3 gal batch.

I also got the 5 gallon paint strainer bags and they are way too small for All Grain. I fit in the grains, but it was so tight I couldn't stir. Got one from the LHBS that actually fits, it's a lot easier.

The 5 gal bags are just right for me. 10lbs grain fits perfectly in a 5 gal cooler with a 5 gal paint strainer. The bag lines the cooler, so you can stir the grain as normal.

For me, my efficiency went way up when I went to the bag method. Got about 82% on a cream ale this weekend.

I am currently using a 5g IGLOO cylindrical with a 5g strainer bag that I can fit about 12-13# grain in and im getting about 80%...I have a 15g Sanke conversion for MLT and Boil kettle that are currently in the process of being cut...All in all the 5g IGLOO w/ the strainer bag works great for small to moderate batches...In fact I just did a wonderful Golden Strong that started at 1074 and finished at 1012...

andrewp said:

the 5G paint strainer bag i got at LOWES fit nicely over my 5 and 7 1/2 gallon kettles.

whats the best way to improve efficiency using this method. i brewed like this and got OG 1.040 when it was supposed to be around 1.055. Mashed for 90 minutes at 152 and single sparged at 170. I know I didn't boil off enough water (about 1/2 gallon left in the kettle) but that shouldn't account for that much of a miss.

this is my grain bill:
5 lb American Two Row
1 lb Crystal 10

will the crystal 10 not convert as much, thus accounting for the large miss since 16% of the grain bill is crystal. 5 lbs of American 2 Row should yield 1.040 for a 3 gal batch.

Click to expand...

If you did BIAB, no need to sparge. Best way to up your efficiency is to do a 10 min mashout at 170, stir, pull out the bag, dunk a few times, and then let it drip drain above your BK for the entire boil.

For a 6 lb grain bill you should have been around 1.047 pre boil collecting 3.6 gallons after the mash and starting with 4.32 gallons. Your post boil gravity would depend on your boil off. If I had to guess, you used too much water to start with.

andrewp said:

the 5G paint strainer bag i got at LOWES fit nicely over my 5 and 7 1/2 gallon kettles.

whats the best way to improve efficiency using this method. i brewed like this and got OG 1.040 when it was supposed to be around 1.055. Mashed for 90 minutes at 152 and single sparged at 170. I know I didn't boil off enough water (about 1/2 gallon left in the kettle) but that shouldn't account for that much of a miss.

this is my grain bill:
5 lb American Two Row
1 lb Crystal 10

will the crystal 10 not convert as much, thus accounting for the large miss since 16% of the grain bill is crystal. 5 lbs of American 2 Row should yield 1.040 for a 3 gal batch.

Click to expand...

My technique for my first BIAB was this:

60 min mash at 154
lift bag and squeeze it over BK
dunk bag in bucket of 170 deg water, lift and lightly squeeze again
pour bucket content into BK


I got 85% doing this. I was quite surprised, as I was planning on 65-70. I know the squeezing and dunking in the bucket may disqualify it from being a "pure" BIAB, but it worked nicely for me.

HarkinBanks said:

If you did BIAB, no need to sparge. Best way to up your efficiency is to do a 10 min mashout at 170, stir, pull out the bag, dunk a few times, and then let it drip drain above your BK for the entire boil.

For a 6 lb grain bill you should have been around 1.047 pre boil collecting 3.6 gallons after the mash and starting with 4.32 gallons. Your post boil gravity would depend on your boil off. If I had to guess, you used too much water to start with.

Click to expand...

how do you know what volume of water to use for your mash-out?

this actually sounds similar to what i did but i guess i used way to much water. i think i had around 5 gallons pre-boil and i know i also did not boil off enough.

andrewp said:

how do you know what volume of water to use for your mash-out?

this actually sounds similar to what i did but i guess i used way to much water. i think i had around 5 gallons pre-boil and i know i also did not boil off enough.

Click to expand...

Well if you did BIAB, there is no sparge or mash-out addition. You start with your total water volume and subtract the grain absorption amount. After your mash, you just add heat to raise the temp to 170 for around 10 minutes while stirring. Then just remove the bag and let it drain.

If you added water for the mashout, that is why you had too much water.

Here is a pretty simple example for your 6 lb grain bill:

Total water into the kettle = 4.32 gallons
Loss to grain absorption (.12g/lb) = .72 gallons
Pre-boil volume = 3.6 gallons
Boiloff amount on an avg. gas stovetop = .58 gallons
Post boil volume = 3.02
Loss to trub = .16 gallons
Volume into fermenter = 2.85 gallons

To another post, I would not squeeze the grain bag. This can extract tannins and is not something I would advise. I let my bag drip drain over my BK the entire boil. I get most of the wort out this way.

How did you make those calculations?

To be honest I have an iPod app (BrewCloud) and just followed the water instructions it gave me.

andrewp said:

How did you make those calculations?

To be honest I have an iPod app (BrewCloud) and just followed the water instructions it gave me.

Click to expand...

Once you know your boiloff rate it is all pretty simple, just subtract your losses by hand based on your experience and system. In my experience I get .12g/lb grain absorption, a .58 gal boiloff in 60 mins on my gas range, and a .17 gal loss to trub when I do small batch BIAB. Your setup may be different. I have different losses on my full batch Brutus 20 system.

I have an excel spreadsheet that calculates everything automatically based on my grain bill and my intended batch size. BIAB calcs are very easy though, you don't need any of those new-fangled apps. Best thing I ever did was sit down with an excel spreadsheet to understand how the computer programs calculate things. You will learn a lot about brewing if you do this.

thanks for the help