If post mash SG is good why check the OG?

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

raysmithtx

Supporting Member
HBT Supporter
Joined
Sep 8, 2012
Messages
715
Reaction score
188
Location
Fort Worth
Using Beersmith. If I hit my post mash volume and SG why do I need to check the OG? I know the amount of sugars that are present so if I hit my post boil volume doesn't that mean my OG will be correct too?
 
You don't really need to if you don't want to bust most folks do just to make sure. It's helpful to know if your efficiency is correct post boil. Also so you can know the specific amount of alcohol in the beer.
 
Also if you don't boil off enough you'll come in low on your fg so I take a refractometer reading at the end of boil and if I'm low I'll just boil a little longer.
 
I'm not really following the logic in the previous two replies.

You are correct. I check after mash to make sure things went well and so I can make any adjustments with dry extract if desired. I also check before pitching just to confirm, especially since I don't have a method to measure post boil volume accurately.
 
Because your pre boil gravity or mash sg as you say will be different if you don't boil off enough which is what your ultimate og is based off of, that and like u said hitting your pre boil volume and gravity. To low a pre boil gravity in your expected amount of pre boil volume means your efficiency was not as expected and you'll need to boil off more to hit your desired og. The pbg and og aren't necessarily one to one if something throws one off whether it's poor efficiency or not boiling off enough or boiling off to much.
Hope this helps.
 
If you collect the proper amount of wort at the right gravity preboil, and boil to the right amount post boil you don't NEED to check OG. Checking confirms that you read properly for the preboil gravity, collected the proper preboil volume and ended up with the proper volume post boil. This allows you to calculate the ABV accurately. I always check and record the OG but rarely calculate the actual ABV. I can look at my notes and make the calculation if I decide I want to.
 
Back
Top