I brew with extracts as I don’t have enough time or storage to do all grain. I mainly brew or try to brew beers that I grew up with and some others that look like I might like them; usually bitters and ipas although I’ve just done a mosaic ipa.

A year ago I started using the Brewfather app with the recipes from Grahams book just to see if I was using the right amount of hops as my alpha acids were different to those in the book. By becoming familiar with the software I have grown more confident with it. However I never used the brew function as this appears to be for all grain only. Also the boil volume shown on the recipe page is for all grain too.

A few weeks ago I finally started reading about hop utilization and realised that the numbers I was getting for my recipes were wrong as I normally just do a small boil then topped up at the end after cooling and then adding more cool/warm water to get to my final temp.

I have worked out a workaround for the boil volume to hopefully get the correct numbers. Here’s how it goes.

Disclaimer…my workaround might be totally off as I have no way of checking the actual numbers but I believe my reasoning is sound and I am highly open to anyone who can throw in their opinions and alternative reasoning.

After I have created my recipe usually for 6US gallons (sorry for using old money- even tho I am fluent with metric I am living in the US and it is easier for me with the equipment I have) I then look at the batch volume and pre-boil volume. 6gallon batch and 7.32 gallon preboil. So if I were to do a boil of this size my numbers would be correct. However I usually do a roughly 3 gallon boil. So what I do is change the batch volume to 1.85 gallons…and this changes the boil volume to 3 gallons.

Then I check the numbers for the hops and adjust the hops weights to get double the number I need so if the final required number is 42 I adjust the hops to create 84 ibu. I think of this 84 as a finite fixed number in a volume of 3 gallon. Also and this is probably affecting any Maillard reactions going on..during the boil I add 1/4 gallon of boiling water every 15mins throughout a 1 hour boil to try to keep the volume at 3 gallons. It is also probably achieving more IBUs too…but not to a great deal I think.

Then after the boil I cool the wort as normal , in the sink with ice, to get the temp down as much as I can then add cold water to get it to my usual temp of 68F and final volume of 6 gallons.

So now I have a finite number of 84 ibu in a doubled volume from 3 to 6 gallons so I can simply half the 84 back to 42ibu. When putting back the correct volume of 6 gallons on the recipe the resultant numbers change again but I know the hop amounts should be more correct than they had been .

I am very curious to hear from anyone with any thoughts on this idea.

## Using Brewfather software for extract recipes and hop utilization

### Re: Using Brewfather software for extract recipes and hop utilization

There is a small addition to the previous post…

Some time ago when I was making Krupnikas, I wanted to lower the alcohol content of the krupnikas from 95% down to about 50.

The problem is I had no way of knowing how much water to add to the amount that I’d got. I mentioned this problem to my brother who is a Maths teacher and he came up with an equation which I could use.

Start volume((actual abv%/required abv%)-1)=water required to achieve required abv%

This worked out great…so back to the hop utilization.

I also have done 5 gallon brews where I end up just adding 2 gallons at the end of my 3 gallon boil. This caused a problem with what my required hop numbers needed to be so here where the above equation helped out again.

I re-worded the equation as follows..

Final boil volume((achieve IBUs from boil/required final IBUs in fermenter)-1)=water additions for final volume.

A useful rearrangement is to find out what IBUs are needed from a boil for a final volume…

eg if I’m doing a 3gallon boil and my batch is for 6.5 gallons and my final required IBUs are 42. Rearranging the above equation gives ..

Achieved IBUs from boil=(water additions for final volume(3.5gal)/final boil volume(3) +1) X required IBUs in fermenter(42)….=((3.5/3)+1)x42=91

So in the above example I need to get 91 IBUs in my recipe for a boil of 3 gallons and adding 3.5 gallons for a total batch of 6.5 gallons.

To do this in my recipe in BF I change the batch to 1.85gallons which makes the boil volume 3gallons. Then I adjust the hops to achieve IBUs of 91

In theory this then should produce the desired 42 IBUs in my final 6.5 gallon batch.

No change is needed for the equation to work with litres.

I hope all that made sense.

Some time ago when I was making Krupnikas, I wanted to lower the alcohol content of the krupnikas from 95% down to about 50.

The problem is I had no way of knowing how much water to add to the amount that I’d got. I mentioned this problem to my brother who is a Maths teacher and he came up with an equation which I could use.

Start volume((actual abv%/required abv%)-1)=water required to achieve required abv%

This worked out great…so back to the hop utilization.

I also have done 5 gallon brews where I end up just adding 2 gallons at the end of my 3 gallon boil. This caused a problem with what my required hop numbers needed to be so here where the above equation helped out again.

I re-worded the equation as follows..

Final boil volume((achieve IBUs from boil/required final IBUs in fermenter)-1)=water additions for final volume.

A useful rearrangement is to find out what IBUs are needed from a boil for a final volume…

eg if I’m doing a 3gallon boil and my batch is for 6.5 gallons and my final required IBUs are 42. Rearranging the above equation gives ..

Achieved IBUs from boil=(water additions for final volume(3.5gal)/final boil volume(3) +1) X required IBUs in fermenter(42)….=((3.5/3)+1)x42=91

So in the above example I need to get 91 IBUs in my recipe for a boil of 3 gallons and adding 3.5 gallons for a total batch of 6.5 gallons.

To do this in my recipe in BF I change the batch to 1.85gallons which makes the boil volume 3gallons. Then I adjust the hops to achieve IBUs of 91

In theory this then should produce the desired 42 IBUs in my final 6.5 gallon batch.

No change is needed for the equation to work with litres.

I hope all that made sense.