Hydrometer Question

[betelgeuse4721]

Hey all,

I usually boil with about 3 gallons and then transfer the wort into my primary and top it off with sanitized water to hit the 5 gallon mark.

For my hydrometer sample . . .

Does it matter if I take the sample of the condensed wort VS taking a sample of the 5 gallon wort?

Just making sure my readings will be accurate.

Thanks a bunch,
Brady

 

[MarcMTL]

Absolutely. You ferment the whole 5 gals, and not jsute the 3, right?

Adding water will dilute the wort, and lower your SG. Take the reading of the whole 5 gallons.

Good luck!

 

[Dahoov]

Well, yes sort of. If you can accurately measure (in fluid ounces) the volume of the wort and water you can calculate what the gravity of the combined volume will be. The formula is (OuncesBoiledWort * GravityBoiledWort) + OuncesFreshWater) / TotalCombinedOunces = TotalGravity

Example, if you had exactly 3 gallons of boiled wort at 1.070 and you wanted to have exactly 5 gallons in the fermenter.

(384 * 1.070) + 256) / 640 = 1.042

Someone please check my math on this one

Since you would have to accurately measure both volumes before mixing them it would be easier to just take the gravity reading of the total.