Full 5G Boil, after down to ~4. Add Water?

[uofmguy]

Hi,
I just finished my first brew. Things went well, kind of. At least I know what I need to do for the next one haha.

Anyway, I started boiling with a full 5 gallons, but when I siphoned into the fermenter, I found that I had a little over 4 (boiling off water and what not). Do I add enough water to make 5 gallons or since I started with 5, I just let it be?

 

[Hello]

Depends. What was the anticipated specific (original) gravity and what is your gravity right now? If it is high, your gravity is higher than the anticipated, go ahead and top off if you want. If it is lower, leave it. No one said you have to have 5 gallons.

Also, you will now want to account for boil off and trub loss on a go forward.

 

[dstranger99]

You will always lose some during fermentation, especially if there's at least 1 inch of trub leftover in the vessel.

 

[davygoat2]

see what your gravity is supposed to be after the boil.
If it was me.if it's too high
i'd add boiled or bottled water

 

[dstranger99]

Hell, I read OP's post wrong, I thought this was after fermentation, not the boil..........lol..........

 

[masonsjax]

I start with a pre-boil volume of 7 gallons for a 60 min boil, 7.5 gallons for a 90 min boil in order to get 6 gallons post boil. I collect 5.5 gallons in my fermenter leavingthe trub behind and usually some wort to freeze for making starters or for replacing spent wort on harvested yeast in the fridge. After fermentation I transfer 5-5.25 gallons of beer into a keg and the rest is yeast and trub.

 

[uofmguy]

Thanks for the help guys. The OG was normal so looks like I'll just have 4 gallons.

Quick question though: If I start out with say 6 gallons of water and it boils down to 5, won't that make my OG lower than where you want it?

 

[dkevinb]

Thanks for the help guys. The OG was normal so looks like I'll just have 4 gallons.

Quick question though: If I start out with say 6 gallons of water and it boils down to 5, won't that make my OG lower than where you want it?

Maybe. The specific gravity is a measure of how much stuff (mostly sugars) you have in so many gallons of water. If you scale your recipe for a 5 gallon batch then you should hit the OG if you wind up with 5 gallons of wort in the fermenter, regardless of how much water you start with. It doesn't matter if you start with more and boil down to 5 gallons, or start with less and top off to 5 gallons. That's why full boils and partial boils wind up with the same OG. However, your ingredients will vary in their starch/sugar content compared to the recipe, so the actual OG may vary a little from the expected OG.

That's not to say that a full boil and a partial boil will give you the same exact beer. There are a lot of other factors in play (hop utilization, etc.), but the specific gravities should be the same.

 

[uofmguy]

Cool. Makes sense

 

[Yooper]

Thanks for the help guys. The OG was normal so looks like I'll just have 4 gallons.

Quick question though: If I start out with say 6 gallons of water and it boils down to 5, won't that make my OG lower than where you want it?

No.

If you're using extract, and the recipe is designed for 5 gallons, you want to have 5 gallons in the fermenter to exactly match the recipe.

I always start with 7 gallons for a finished 5 gallon batch- but I live in a dry(ish) climate and boil off nearly 2 gallons an hour!

If you start with 5 gallons, and boil off a gallon an hour, which is most typical, then you would have 4 gallons when you're done. Add a gallon to the fermenter, and boom!- 5 gallons in the fermenter. It really is that simple.