5 gallon batch vs. 6 gallon batch

[roadhouse]

First off, I was wondering where the 5 gallon batch came from? Typically I make 6 gallon batches to compensate for loss during transfer, hop absorption, and generally to get more beer. I know that a 6 gallon batch will be lighter in color and have less IBUs, but flavorwise, how much of a difference is it going to make as far as doing 5 gallons against 6 gallons? I never really thought about it because I just aim for 6 gallons from the start when formulating recipes.

[Dangerous Beans]

"I know that a 6 gallon batch will be lighter in color and have less IBUs"
If you adjust for the fact that your making more beer, you should be able to get the same colour and IBUs/gal.

My guess is that 5 gal came from the size of the fermenters most people had. Once enough people were using 5 gal as the standard size, others just followed along.
You see it here, with people giving recipes for ~18L (5gal)

[roadhouse]

The problem with it seems to be that in order to get the same color and proportions you end up with more uneven numbers like 5 oz instead of 4 oz, or 10 oz instead of 8 oz. Thinking about scaling my recipes down to 5.5 gallons since right now I still tend to use those even amounts like .5 lb, .25 lb, etc and usually up the base malt.

[Carl Spakler]

The problem with it seems to be that in order to get the same color and proportions you end up with more uneven numbers like 5 oz instead of 4 oz, or 10 oz instead of 8 oz. Thinking about scaling my recipes down to 5.5 gallons since right now I still tend to use those even amounts like .5 lb, .25 lb, etc and usually up the base malt.

There is no magic to 5 gallons that always results in even numbers for the ingredients, my guess is that once the standard 5 gallon was set people made recipes come out neatly for 5 gallon batches. Now when you try to add 20% to the voulme you add ~20% to the ingredient list so a nice, round 4lbs of grain becomes 4.8 lbs, etc. Had a 6 gallon recipe become the de facto standard the recipe would lilely have been 5 lbs and to scale down to 5 gallons you'd have the uneven 4.16 lbs.

IMO brewing is not a 100% controlled environment, just look at the range of brewhouse efficiencies people report. Two brewers with different skill levels given the same ingredients would likely end up with two different OG and FG levels. Some brewers even report differences when they brew the same recipe multiple times.

Use a brewing software tool to get in the ballpark and then adjust if need be to your taste/skill/equipment.

[Mill Rat]

Two reasons for the 5-gallon standard. It's easy to find containers in that size, and it's about the maximum weight that most people can safely and adeptly maneuver with bare hands.

[darylM]

I am going to agree with Mill Rat. I have a brewpot that can handle a 10 gal boil. Lifting it in a way that is safe and possible by hand is nearly impossible when there is 10 gals in it. When it gets into the fermenter, I am more dragging it sometimes than carrying it.

[markaberrant]

I make 6 gallon (23L) batches - for some reason, us crazy Canucks do it this way. I guess we just like more beer.

[Dangerous Beans]

I'm doing ~6 Gallon (actually 25L) batches too. My fermenter can hold 6gal with spare space, and this way I get more beer for the same amount of effort.

[markaberrant]

6 US gallons = 22.71L
6 Imperial gallons = 27.28L