Beersmith Ibu ?

[juzz1981]

Hi,

Just trying to get beersmith setup for calculating IBU although it doesn't seem correct to me, not sure what ive done wrong as 30g of 11.3% Hops with a 60min boil should be alot higher than what the program is stating.

Any idea's what ive cocked up?

 

[opposition]

Jump on their website.

I think the support section shows that it uses a different formula.

 

[kelbygreen]

havnt used beer smith for a while but if you done it like I done the first time then this is what I would do.

Take out the 23lt local water
take out the pale malt (or change the values to 700gl) then double click (i think and add at 60mins in boil)
put in the rest of the pale malt in (1.8kg) and set it at 0min in the boil

As it default adds the full 2.5kg of malt to the 6lt boil. and the water well the batch size is already set so I found adding water did nothing

 

[kelbygreen]

Oh add the dextrose in at 0min in the boil as well.

Also maybe do 23g of POR at 45 and 13g of POR at 15min. Got that off tony and his POR ale tastes bloody awsome think its bittered to around about 26IBU and OG of 1.048

 

[groucho]

You haven't done anything wrong.

Your IBU is low because your boil volume is only 6liters. That 6 liter boil will be quite high in gravity and therefore hop utilization will be low. Try adjusting that boil volume and see what happens to the IBUs. Typically if the mash was all-grain, the boil volume would be more like 30-32liters to end up with 23liters into the fermenter.

Also, with the dextrose, there is a selection to add it at certain time from the end of the boil (or even to add it at the end of the boil). This will affect the IBUs as adding it to the boil affects the wort gravity.

One more thing that affects the IBUs, is the method used to calculate it (ie Rager, Tinseth, or Gartez). You can change the method in the preferences.

Hi,

Just trying to get beersmith setup for calculating IBU although it doesn't seem correct to me, not sure what ive done wrong as 30g of 11.3% Hops with a 60min boil should be alot higher than what the program is stating.

Any idea's what ive cocked up?

 

[juzz1981]

thanks guys,

this should be better

 

[kelbygreen]

that looks a bit better . took me a bit to work out why IBU was all screwed up to begin with haha then found it was dumping the lot in at 60mins so had to itemise it a little bit more to get the right boil SG

 

[bcp]

IBU is all over the place, and i'm not sure it's related to time in the boil. Just for example, with a Riggwelter Yorkshire Square ale recipe...
* With 'Set Boil Volume...' selected, the boil volume defaults at 13 litres, & IBU=26. (Way too low for the recipe)
* Unselected I change boil volume to 29 litres, IBU=41.2 (Ok, maybe greater extraction from higher water volume & lower malt density?)
* Just for fun, change boil volume to 500 litres, IBU=61.4 Yeah, right. Where's the law of diminishing returns here?

Are any of these actually correct?

My equipment setup for background information: (Please correct if you know something i don't)
BIAB in birko 40litre urn.

MASH PROFILE
At the moment my mash profile is Single Infusion, Full body, No Mashout.
Mash type - temperature
Water to add 32litres (because that's approx what i mash in with)
Step time 60 minutes.

MAIN RECIPE SCREEN
Unselect 'Set Boil VOlume Based on Equipment' - which sends the IBU down
Change "Boil volume" to 29 litres - IBU goes sky high.

EQUIPMENT
Mash tun volume 40l
Mash tun weight 5.1kg
Material Stainless steel
Mash tun specific heat 0.120
Select calculate boil volume automatically
Evaporation rate 11%
Loss to trub 2.5L (someone on BIABBrewer told me this should be set to zero)
Top up water 0.00
Final volume 23litres

EDIT: Didn't realise this old post was in kits/extracts.

 

[felten]

The losses to trub and cooling loss % will throw the numbers off. Set your batch size to your end of boil volume, and your boil size to your start of boil volume and it should be fine.

 

[bcp]

The losses to trub and cooling loss % will throw the numbers off. Set your batch size to your end of boil volume, and your boil size to your start of boil volume and it should be fine.

Ok, that's very helpful. Just to be crystal clear - if i want 23litres in the fermenter, i need to set batch size higher to include losses to trub, correct?

 

[felten]

Right, the batch size should be the total end of boil volume, trub included. But you want to leave the trub losses field empty as it can throw the calcs out. Have a play with it IE. 25L batch gives x IBU, 20 L batch + 5L loss to trub gives y IBU. But in theory they should be the same.

As for a massively high boil volume giving higher IBU readings, I think it has something to do with the more diluted boil will extract more IBU's, just like more concentrated boils will extract less; at least it does in the calculations. (it might change depending on formula as well, I use tinseth)

[edit] I hope that's right anyway, I just woke up @_@