Quick question: Brewmate settings for BIAB

[stm]

I am planning my first BIAB AG in a 40L Crown urn, and am attempting to set up Brewmate to help with this.

My searches of AHB have left me confused as to whether, in order to get the correct grain and hop bills, I should:

1. set "Losses to trub and chiller" to 0 and bump up my "Batch Size" accordingly (eg, to 25L, assuming trub loss is about 2L), or

2. set "Losses to trub and chiller" to 2L and set my "Batch Size" to 23L (ie, the volume into FV that I want).

I am doubly confused because when I try either option, Brewmate is giving me different bills, but my understanding of the theory is that the bills should be identical because your post-boil volume is the same. Only the brewhouse efficiency is affected. Could someone please let me know what I need to do. Thanks in advance!

STM

 

[seamad]

go option 2

keep good records as your first couple of brews won't be spot on, but record keeping will allow you to nail the numbers after awhile.

 

[stm]

Thanks for that. I've just had another play with Brewmate, as per option 3 (batch size 23L), but then I changed trub loss to a crazy 10L (keeping batch size steady), and it gives me (for example) the same IBUs with the same hops as for trub loss set to 2L or to 0L. That is surely wrong?

If you keep the hops the same but increase the water, you dilute the bitterness, and thus you should be reducing the IBUs as you increase the trub loss setting. But Brewmate doesn't do this.

 

[Crusty]

I am planning my first BIAB AG in a 40L Crown urn, and am attempting to set up Brewmate to help with this.

My searches of AHB have left me confused as to whether, in order to get the correct grain and hop bills, I should:

1. set "Losses to trub and chiller" to 0 and bump up my "Batch Size" accordingly (eg, to 25L, assuming trub loss is about 2L), or

2. set "Losses to trub and chiller" to 2L and set my "Batch Size" to 23L (ie, the volume into FV that I want).

I am doubly confused because when I try either option, Brewmate is giving me different bills, but my understanding of the theory is that the bills should be identical because your post-boil volume is the same. Only the brewhouse efficiency is affected. Could someone please let me know what I need to do. Thanks in advance!

STM

I use BrewMate & have a 40lt Crown Urn. I do 23lt batches & set my trub loss to 2.5lt. If I squeeze the bag pretty hard as I do, last batch I ended up with 20lt into my cube +4L of trub. 1Lt of that is actually cooling loss ( 4% ) so 20+3=23lt batch. ( 24lt of total wort produced )
With that 4L of trub, if I actually leave it cool to room temp, it will lose that 1lt so it's really 3lt to trub.

 

[Crusty]

Thanks for that. I've just had another play with Brewmate, as per option 3 (batch size 23L), but then I changed trub loss to a crazy 10L (keeping batch size steady), and it gives me (for example) the same IBUs with the same hops as for trub loss set to 2L or to 0L. That is surely wrong?

If you keep the hops the same but increase the water, you dilute the bitterness, and thus you should be reducing the IBUs as you increase the trub loss setting. But Brewmate doesn't do this.

If you changed your trub loss to 10lt & kept your batch size the same, ie: 23lt, the IBU ain't going to change, all you are doing is making the programme adjust your strike water volume to compensate for the trub loss so instead of striking in with 32lt or so, you'll now be striking in with 42lt or so, you kept your finished batch size the same so the IBU won't change, it's still 23lt.

 

[stm]

Thanks for your replies. I am still not entirely sure what I am doing, but I suppose the best way to understand is to do it and see how the numbers come out and then adjust for my system, as suggested earlier. Thanks again.

 

[Crusty]

Thanks for your replies. I am still not entirely sure what I am doing, but I suppose the best way to understand is to do it and see how the numbers come out and then adjust for my system, as suggested earlier. Thanks again.

I am using the same urn as you & assuming you have the exposed element urn, your set up would be pretty much identical to mine & I've got my numbers bang on.
If you set your losses to trub & chiller @2.5lt & your Grain absorption ( L/KG ) @0.60, use a grain bag for your hops & boil for 60mins, I think you'll be on the money. Just work out when you get your final volume of wort made what efficiency you actually got. I work all my beers out @80%.

 

[eloschgimpel]

I'm having the same problem as stm with BrewMate's. It does not take kettle loss into account when calculating IBUs or OG, which cannot be correct.
Here's the scenario, you can try this yourself:

Using the, in my case, correct loss of 2.5L with a specific grain bill and a target batch size of 23L, will give me the exact same values for IBU and OG as with a loss of 10L or any other ludicrous volume.
Say you set loss to 10L, leaving the grain and bill untouched. BrewMate will correctly adjust the strike water volume, by adding those extra 7.5L plus some for boil off.
That means where before I'd be extracting my grain in say around 35L of water, I'd now steep the same amount of grain in almost 45L.

Still it does not have an effect on the calculated OG in BrewMate, which will show the same OG with both loss / mash volume values.
I too feel that I am better off setting loss to 0L and changing my batch size target to 25.5L (23L + 2.5L, ignoring the 4% chill shrinkage).

If you changed your trub loss to 10lt & kept your batch size the same, ie: 23lt, the IBU ain't going to change, all you are doing is making the programme adjust your strike water volume to compensate for the trub loss so instead of striking in with 32lt or so, you'll now be striking in with 42lt or so, you kept your finished batch size the same so the IBU won't change, it's still 23lt.

How could adding the same amount of malt and hops to either 32L or 42L result in the same IBUs and extract gravity? It's not like that higher amount of water is boiled off (beyond the partial evaporation applying to the entire kettle volume). Instead it is supposed to be lost or left behind in the kettle, along with whatever hops and sugars it contains. If you add 1kg of sugar to 5L of water and measure the gravity of the lot, the result will be sweeter than adding 1kg of sugar to 7.5L of water, then syphoning off 5L while "loosing" 2.5L. It's simply a weaker concentration.


This has been causing me some confusion when transferring recipes into BrewBuilder at Mark's Homebrew, which obviously DOES take kettle loss into account by applying the grain bill to the full volume in kettle at the end of boil.

 

[stm]

In the end I gave up on Brewmate and found BIABacus, over at biabrewer.info. This is easy and logical to use and is spot on with its numbers.