Double Batch - High Gravity Brewing

[hughman666]

Hi all,

I have a system capable of comfortably brewing 25-30L batches. Today however I am planning to mash in double the amount (10kg) of grain and then top up with water after the boil to achieve 2 x 25L batches.

My question is around the hop additions. Is it a straight 1:1 ratio for the hop addition increase (ie do i just double the amount of hops), or is there some other formula to use when brewing this way?

 

[Dave86]

Hi all,

I have a system capable of comfortably brewing 25-30L batches. Today however I am planning to mash in double the amount (10kg) of grain and then top up with water after the boil to achieve 2 x 25L batches.

My question is around the hop additions. Is it a straight 1:1 ratio for the hop addition increase (ie do i just double the amount of hops), or is there some other formula to use when brewing this way?

Short answer: No. You're hop utilisation will drop with a higher gravity wort, which means you'll need to use some brewing software to figure out how much to increase your bittering hops by. I'd increase the rest of your additions by 1:1 ratio and just play with the bittering addition to achieve the right level of IBUs

 

[dicko]

Hi all,

I have a system capable of comfortably brewing 25-30L batches. Today however I am planning to mash in double the amount (10kg) of grain and then top up with water after the boil to achieve 2 x 25L batches.

My question is around the hop additions. Is it a straight 1:1 ratio for the hop addition increase (ie do i just double the amount of hops), or is there some other formula to use when brewing this way?

Hi, Hughman666,

I used to do exactly that until I increased the size of my brewery and Dave86 is correct in what he says, however, I could not find any definitive info on the amount of increase so I just went with a 1:1 ratio.
The beers I did in this manner all turned out fine and I was happy with the result.
If you are brewing something for a competition that you feel needs to be spot on then brew the smaller batch but for a beer to enjoy at home just go for it.
Note down your results and tasting notes and adjust as you think necessary.

Cheers

 

[Cortez The Killer]

Do you use brewing software?

Promash/Beersmith both allow you to do concentrated batches with top up water and calculates IBU's in higher gravity wort with the Ranger formula selected

Cheers

 

[peas_and_corn]

I normally do a 1:1 ratio and have a look at my figures (as I use promash). However, I rarely aim for a certain style, just what IBUs I think will taste nice. The odds are that doing a 1:1 will be fine- and if not, well you can do another batch with more hops next time, it's not like it will taste awful if you're 5IBUs under

 

[matho]

here is an exel spreadsheet for hop ibu's using john palmer's equation's
just fill in the white squares and it will calculate the IBU's

It's fairly basic but it might help

cheer's matho

i forgot to mention the gravity = boil gravity, volume = the final volume in the fermenter. it does not take into account wort wasteage

 

[David Sinclair]

So i take it if your doing a double batch i.e. boiling double, you add double the hops? which means doubling the IBU's?

Is that right... i've got a feeling i'm in for a education here ...

 

[peas_and_corn]

If you're using double the volume, then you would need more of the oils that add bitterness to the beer. So doubling the hops will increase the amount of bittering oils, but it will be diluted in double the wort, and as such the IBUs will be about the same. I'm sure that there are equations for all this, but I have promash and an arts degree.

 

[matho]

i just found a problem with the spreadsheet the F9 cell should be divided by C4 not C5
here is a fixed copy.
I put the spreadsheet together just to show that if you dilute the wort it is 1:1 but if you increase the gravity it is not, also the increasing boil time above 90 min will not increase utilization very much

cheer's matho

 

[David Sinclair]

If you're using double the volume, then you would need more of the oils that add bitterness to the beer. So doubling the hops will increase the amount of bittering oils, but it will be diluted in double the wort, and as such the IBUs will be about the same. I'm sure that there are equations for all this, but I have promash and an arts degree.

Hope this is the case just did my first double batch (38L)and close enough doubled the hops, hope it is not too bitter....

Also that's a nice little program you got there Matho, will double check with that next time.