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BIAB Efficiency

[quote=“dannyboy58”]Very timely post for me as I plan to do my first BIAB early next week. Crusty, the overview of your brew day was quite helpful and lined up with things I’ve gleaned from Denny and some others in these forums.

Couple questions though… I have a 9 gallon kettle and have been doing full boil extract batches beginning with about 6.6 gallons to get something like 5.25 going into the primary. Should I expect about the same or a little more boil down?

I ordered grains from NB and asked them with a note on my order to double crush the grains. Does anyone have experience with that? Should I expect that they’ll double crush them or no?

Does everyone use something like a false bottom in their kettle to keep the bag off the bottom? This just occurred to me in reading Crusty’s post.[/quote]

Boil off will depend on your kettle set up. A shorter wider kettle will boil off slightly more than a taller thinner kettle. This also depends on what you use to boil, gas or electric & ultmately, how hard you drive the boil. In the past, I boiled fairly hard & would lose 8 litres in an hour with my 32jet Mongolian burner. These days, I boil in an electric urn & my boil is very tame & I typically lose 10% over an hour. With a 29-30 litre pre boil, I lose approximately 3 litres. You can double crush your grains & milling the grain a tad finer is ok with Biab. We don’t need to worry about a stuck sparge. Milling too fine will just result in more trub loss so not too fine. Some guys here in Australia that use round stock pots use a round cake cooling rack to keep their bags off the bottom when heating. Make sure the grid is fine enough that the bag wont slip between the grates in the cooling rack.
As far as sparging goes with Biab, I found it a complete waste of time & an unnecessary step. Sparging is simply rinsing the grains & works well with a traditional 3 vessel set up but not as effective with Biab. Simply sacc resting for 90mins followed by heating to 78degC for the mash out will be more than adequate to release those trapped sugars. When I hoist my grain bag via a pulley system, I squeeze as much wort from the bag as possible & then drop the bag into another vessel & squeeze some more. I then add this back to the urn for boiling.

[quote=“Crusty”][quote=“dannyboy58”]Very timely post for me as I plan to do my first BIAB early next week. Crusty, the overview of your brew day was quite helpful and lined up with things I’ve gleaned from Denny and some others in these forums.

Couple questions though… I have a 9 gallon kettle and have been doing full boil extract batches beginning with about 6.6 gallons to get something like 5.25 going into the primary. Should I expect about the same or a little more boil down?

I ordered grains from NB and asked them with a note on my order to double crush the grains. Does anyone have experience with that? Should I expect that they’ll double crush them or no?

Does everyone use something like a false bottom in their kettle to keep the bag off the bottom? This just occurred to me in reading Crusty’s post.[/quote]

Boil off will depend on your kettle set up. A shorter wider kettle will boil off slightly more than a taller thinner kettle. This also depends on what you use to boil, gas or electric & ultmately, how hard you drive the boil. In the past, I boiled fairly hard & would lose 8 litres in an hour with my 32jet Mongolian burner. These days, I boil in an electric urn & my boil is very tame & I typically lose 10% over an hour. With a 29-30 litre pre boil, I lose approximately 3 litres. You can double crush your grains & milling the grain a tad finer is ok with Biab. We don’t need to worry about a stuck sparge. Milling too fine will just result in more trub loss so not too fine. Some guys here in Australia that use round stock pots use a round cake cooling rack to keep their bags off the bottom when heating. Make sure the grid is fine enough that the bag wont slip between the grates in the cooling rack.
As far as sparging goes with Biab, I found it a complete waste of time & an unnecessary step. Sparging is simply rinsing the grains & works well with a traditional 3 vessel set up but not as effective with Biab. Simply sacc resting for 90mins followed by heating to 78degC for the mash out will be more than adequate to release those trapped sugars. When I hoist my grain bag via a pulley system, I squeeze as much wort from the bag as possible & then drop the bag into another vessel & squeeze some more. I then add this back to the urn for boiling.[/quote]

I have a 9 gallon pot so my other concern is the volume created by 10 pounds of grain. A 6.5 gal boil rolling boil requires close monitoring.

You will be pushing it for full volume. For a 23lt batch size, allowing 10% boil off, 2.5lts loss to trub loss & a grain absorption rate of 0.60l/kg, my mash volume with the bag & 5.080kg of grain is 37.53lt. When I raise the bag ready to boil, I usually have 29-30lts of wort for the boil. I have a 40lt urn that I brew in so I do have some spare room.
Sorry about the Litres & Celcius guys, just the Aussie lingo… :cheers:

[quote=“Crusty”]You will be pushing it for full volume. For a 23lt batch size, allowing 10% boil off, 2.5lts loss to trub loss & a grain absorption rate of 0.60l/kg, my mash volume with the bag & 5.080kg of grain is 37.53lt. When I raise the bag ready to boil, I usually have 29-30lts of wort for the boil. I have a 40lt urn that I brew in so I do have some spare room.
Sorry about the Litres & Celcius guys, just the Aussie lingo… :cheers: [/quote]

No sweat man… I appreciate the info and easy enough for this mic/yank to convert :cheers:

This is the urn that I brew in.

http://www.craftbrewer.com.au/shop/details.asp?PID=3912

This is the roasting rack that covers my exposed element in the urn.

This is the No Chill cube that I use for all my beers.

http://www.craftbrewer.com.au/shop/details.asp?PID=2939

Cheers

Just a note on the melting bag thing…I did only two extract batches before saying “Screw This!” and went BIAB while I get up the money for a 10 gallon pot to go all grain. I use muslin bags like at the brew store, as they will not melt when using an electric stove. I did however, make my own with muslin from a fabric store and my trusty Singer sewing machine. That way I have the size I need, and for way less money. If you go this route, use multiple runs of a zigzag stitch to sew the seams, a straight stitch will not do!

as a very late addendum, I have started off well, using 2 ct. 5-gallon paint straining bags from Lowe’s. I hook each around a handle on my mash pot, and I’m off. (also they cost $2 each). Efficiency ranges from 88% for an ESB to 75% for a high grav. sparging is with a pasta colander and adds considerable sugars. Good stuff.

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