Spike Brewing 12.5 Conical Fermenter Giveaway - Enter Now!

Home Brew Forums > Home Brewing Beer > General Techniques > How much water to add after boil?

Reply
 
LinkBack Thread Tools
Old 09-13-2012, 12:21 AM   #11
Revvy
Post Hoc Ergo Propter Hoc
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
Revvy's Avatar
Recipes 
 
Join Date: Dec 2007
Location: "Detroitish" Michigan
Posts: 40,804
Liked 2728 Times on 1636 Posts
Likes Given: 3485

Default

Quote:
Originally Posted by scorpionc53 View Post
I'd still keep an eye on og. I just filled to 5 gallons once and my og was way off.
Read the link I just posted, and you'll see that more than likely despite what your hydromter may say, the REAL gravity will only be correct if your total volume is correct.
__________________

Like my snazzy new avatar? Get Sons of Zymurgy swag, here, and brew with the best.

Revvy's one of the cool reverends. He has a Harley and a t-shirt that says on the back "If you can read this, the bitch was Raptured. - Madman

I gotta tell ya, just between us girls, that Revvy is HOT. Very tall, gorgeous grey hair and a terrific smile. He's very good looking in person, with a charismatic personality... he drives like a ****ing maniac! - YooperBrew

Revvy is offline
 
Reply With Quote Quick reply to this message
Old 09-13-2012, 01:00 AM   #12
Qhrumphf
Stay Rude, Stay SHARP
HBT_LIFETIMESUPPORTER.png
Feedback Score: 1 reviews
 
Qhrumphf's Avatar
Recipes 
 
Join Date: Apr 2011
Location: Arlington, VA
Posts: 6,267
Liked 1422 Times on 1027 Posts
Likes Given: 603

Default

Quote:
Originally Posted by Revvy View Post

Every brewing software has a tool called a dillution calculator to help people figure out how much water to top off, when the miss their gravity in all grain brewing. If you plug the numbers of even an extract batch into the software you will see how this corrects itself.

It happens all the time. When you calculate your gravity of your current volume and you then use the dillution tool in beersmith to calculate the gravity after toppiing it off with the amount of water you are missing, you almost always come back to what the original gravity should be. I've topped off when necessary and the beer indeed has turned out fine.
(not directed at Revvy but the others on this thread)

The math in those calculators is actually very very simple.

gravity x volume = gravity 2 x volume 2 (expressing gravity as "gravity units". Basically 1.048 would be 48, and 1.072 would be 72).

So if you've done your boil, and you have 2.5 gallons of wort, and your gravity reads 1.090, and you want a 5 gallon batch, 90 x (2.5)=5 x (your OG). You come up with 45, or an OG of 1.045 if topped off to 5 gallons. Alternatively, if you don't care about the volume but want an OG of 1.065, it works the same way. You'd get 3.46, the volume you want to top off to in order to hit that OG.

And it works the same way for AG brewers (or anyone doing full boil, but most critical for all-grain) to scale down the volume, so you know before the boil whether or not you're going to hit your target gravity, and you can either adjust your boil time, your volume, or add more fermentables to make sure you're spot on.

I do partial boil all-grain (since my stove can't boil more than 5 gallons), and this formula makes life so much easier. No more second guessing my gravity readings.
__________________

Up Next: Spiced Winter Warmer, Brett. C. Old Ale
Primary: Best Bitter, English IPA
Secondary: Sour Stout, Wild Bitter
Polypinned: English Summer Ale, Coniston Bluebird Bitter Clone v1.5
Bottled: Sticke Altbier, Doppelsticke Altbier, Weizenbock, Berliner Weisse, Spruce Brown Ale, Arrogant Bastard Clone
Bottled for the long haul: Brett B. Tripel, Quadrupel, Tripel, Brett C. Oaked English Barleywine, Lamebic

Qhrumphf is online now
Revvy Likes This 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options
Thread Tools