How to figure out how much water to add.

[Skullfingr]

I've noticed that during boil, water decreases by almost half. How should I determine, for making recipes, how much water I should have in the fermenter in order to bring the amount to the desired level?

 

[kh54s10]

Are you working from kits or recipes. With kits the directions should state how much water for each step.

If you recipe software you can work with the final volume in mind. Just adjust things until you get what you are looking for in terms of ABV, hop/malt balance.

 

[Skullfingr]

I'm trying to design my own recipes. But I'm also dealing with a very small boil pot, so it gets REALLY tricky.

 

[chickypad]

You need to figure out the boil-off volume for your kettle. That should remain pretty constant for the same level of rolling boil because it's related to surface area. For example, I have a small kettle I use for 3 gal batches that will boil off .6 gal per hr but my big 20g kettle boils of 1.5 gal per hr.

Once you know that you can predict how much top off water you will need. You subtract the boil-off volume from your pre-boil volume to get your post-boil volume. Then add enough top off water to bring you to your batch volume. There is also a 4% volume loss to cooling but on a small boil that should be pretty negligible (for example, only 1/2 qt on a 3 gallon boil, but .5 gallon loss on my big batches).

Also works just marking your fermenter to the desired batch volume, putting in wort first, then top off to the mark.

 

[Hammy71]

Also works just marking your fermenter to the desired batch volume, putting in wort first, then top off to the mark.

Yep, sharpie on the fermenter at five gallons. Like others have said, if/when you start doing full boils you can worry/determine how much your boil off is.

 

[Yooper]

As was said, don't put the top off water in the fermenter first. Because if you have too much, you can't take it out! Add the cooled wort to the carboy, and then top up to 5 gallons with cool water.

Mark your carboy in advance (duct tape or a sharpie line is fine) so you know where to fill the carboy to.

 

[Skullfingr]

Thanks everyone. I'm working with a very crude setup. My pot will only boil a gallon at a time so I have to mash the 4 gallons I'm making, then boil it a bit at a time. So I'll add the desired amount at the end.

Thanks!

 

[dmashl]

walmart sells a 16 qt stainless pot for about $12, thats what i use.

 

[FuzzeWuzze]

walmart sells a 16 qt stainless pot for about $12, thats what i use.

Even better, goto Target or Walmart and buy the 8 Gallon IMUSA Aluminum Tamale pot for 20 bucks, been using it for a while now and for the price its amazing..its no fancy thick walled copper core Blichmann or anything, but for $20 you cant complain and there's nothing it cant do that a higher end one cant really...i mean all the stupid pots are really for is boiling liquid, there's not a whole lot of technology that can make that process better. Things like burning on the bottom can just be resolved with proper heat control.
Your brew days have to be nightmares only doing a gallon at a time like that.

As for your original question, the only sure fire way to know is experience as different pot thicknesses and materials will boil off water slightly faster or slower. In general though i think you can assume at least 1 gallon per 60 minutes with rolling boil. In practice its usually a bit more...

 

[Skullfingr]

I don't know how different our stores are but when I went to those stores, the cheapest one with enough size was well over 50$. If Id've seen any that cheap, I would have already purchased it. Maybe I should go look again.