Scaling recipe riddle

I give up. I'm baffled, unless it has something to do with the hops. Or perhaps you didn't account for the invasion? That will really screw up a beer!

 

My guess would be that it has to do with the amount of liquid that turns to vapor during the boil--

If you start with a gallon and a half, and during the boil it goes down to 1 gallon, you've lost 1/3 of your volume,
but if you start with 6 gallons and boil down to 5, you've only lost 1/6 of it.

I've also read that if you boil a partial batch (wanting to make 5 gallons but only boiling 2 1/2 gallons & then adding 2 1/2 gallons of sterilized water after the boil to bring it up to the full 5 gallons) it will be lower IBUs than if you had just done a full boil... so I'm kind of applying a similar idea to that to the area of scaling.

That being said, I'd have no idea how to fix it.

Again, this is more of a guess on my part, no real science or anything to back it up

 

Linear scaling of the crystal malt should be the right way to do it. Malt bills should remain in the same percentage.

Were these both full boil worts? Did your mash temperature change, or is your thermometer off?

 

Did you by any chance get a higher mash efficiency, perhaps coupled with lower attenuation?

 

There's absolutely no reason why 0.25 lb of caravienna in 1 gallon would be fine and 1.25 lb in 5 gallons would be too much.

 

Agreed.

But 12.5% seems like it shouldn't be fine. I'd expect both beers to be heavy and sweet.

 

I would suspect the issue is in differences in efficiency. If you're using the same process, equipment, etc. you should be able to use the same percentages. If you change any of this though you will get differing efficiencies from your base grains but the same proportion of flavor and extraction from your crystal/roasted malts as they are already "converted" by the malting/roasting process. This can lead to the crystal/roasted characters being overly strong as there is less base malt character to balance it. So what was your efficiency while doing 1 gallon batches and what is your efficiency now that you've stepped up?

 

BU:GU ratio is (number of IBUs) : (Gravity points). Gravity points is specific gravity minus 1 multiplied by 1000. So a 1.048 wort has 48 gravity points.

 

With homebrew sized batches, hops scale fine. Between homebrew sized batches and commercial sized batches, the larger batches enjoy noticeably higher hop utilization.

 

In a session beer like that, I would say 12.5% is about right since it will ferment pretty low anyway.

 

I would say that is why your beer turned out sweet, and less balanced. What do I win?

 

Also, did you pitch enough yeast? How well did it ferment, in comparison?

 

I would say your homebrew store doesn't know what they're doing if they're scaling the same recipe from 1 gal with 1 oz of hops to 5 gal with 5 oz of hops.

 

Or, 1 oz for 1 gallon and 2 oz for 2 gallons either.

 

I'm sorry, too late to edit, that above post should read:

I would say your homebrew store doesn't know what they're doing if they're scaling the same recipe from 1 gal with 1 oz of hops to 5 gal with 2 oz of hops.