Water Volumes

[photek1000]

I'm trying to get my head around a Hobgoblin style recipe I'm planning for next week and the volumes of water required.

It will be a BIAB brewday, the ingredients are an off the shelf pack and consists of approx 5KG grain and 45g of hops, the recipe is aiming for 19L in the FV, all fine so far.

It suggests 17L for the Mash and 19L for the Sparge, plus a possible extra 5 for Losses. (90 minute Mash and 90 minute Boil)(36L total water)

In my head that sounds like a lot of water for a 19L target.

My rough calcs for my gear and a few approx numbers for losses off of this forum would be as follows

Boiler Dead Space - 2.5L
Grain absorbtion - 5L
Hops abs - 0.25L
Boil Off - 2.5L

Aiming for 19L in FV = 29.25Litres required Liqour, so almost 7 Litres less.

Am I missing something here, or just an error in the suggested recipe

 

[Bodleigh Head]

I would take it to mean 17 + 2 + 5 ... total volume of 24 litres for a final volume of 19 ... seems more logical ... but it's not a precise science by any means and will depend a lot on your set up, how powerful your boil is, if you boil with a lid on etc. I am not familiar with BIAB techniques so can't help over and above that.

As a rule of thumb, in my primitive mash tun set-up, I work on a rough calculation of target volume + 25% ... over that and I start extracting tannin which is not very pleasant. Also, 5kg of grain for a 19 litre brew in my set-up would give a starting gravity of about 1060 ... seems a bit strong for Hobgoblin ???

Hope that is of some help :)

 

[strange-steve]

It does sound like a lot. Are you doing full volume BIAB? If so then it's simply the FV volume plus losses, just as you calculated, 29.25L.

 

[geetee]

That's a lot of water in the initial mash, I would use 2.7 x the grain i.e 12.2 litres. You will lose 5 litres to the grain but depening on your evaporation loss rate I would add a further 10 litres ( 2 x 5 batches for me) and this should get you close to 22 litres. Withe evaporation/losses this should go down to 19 or so.

I would agree that it is a tad heavy on liquor to the tune of 7 litres or so.

Don't get hung up on exact volumes as once you have boiled you can check your target gravity and liquor back if it is over strong.

PS Sorry I forgot you are BIAB, my calculation is for a batch sparge method!

 

[photek1000]

Thanks for all the input plenty for me to use to tweak the volumes to what I need,

Maybe it's just the way it's written that makes no sense, and should read sparge back up to 19L plus losses.

Target OG is is the 1050-54 range.

 

[Covrich]

I do full BIAB for 23L and based on a 5KG grain bill my total water which I start with is around 31-32L.. (although I do sometimes end up with around 24)

I think the 29L total amount is a closer figure and you can divide it up there for mash and sparge, assuming the mash will subtract up to 5ls (thats on the higher scale imo) you should end up 24-25 pre boil. Then you have 5 or 6 liters which you have to play with for boil off and losses.

Only real way to find out is either go for it with a trial and error or test your equipment before hand and calibrate it..

 

[Honk]

It does sound like a lot. Are you doing full volume BIAB? If so then it's simply the FV volume plus losses, just as you calculated, 29.25L.

I'm with this, if I was aiming for 19 litres in the fermenter biab I'd start with around 29 / 30 litres depending on length of boil.

(But that's based off not much experience so far and your equipment may vary )