lower OG

Both yesterday and today I brewed and both times my OG was lower than the recipe indicated. Yesterday I brewed a Barleywine with OG of 1.082, mine read 1.072. Today I brewed an English brown ale with OG of 1.052 and mine was 1.042.

1. What are some of the possible reasons this is happening?
2. It is too late to correct it?
3. Does it really matter? What are the consequences?

Thank you,

Jeremy

We get this question 3-4 times every day, so you're not alone. And in reality, nothing's wrong.

It's a pretty common issue for ANYONE topping off with water in the fermenter (and that includes partial mashes, extract or all grain revcipes) to have an error in reading the OG...In fact, it is actually nearly impossible to mix the wort and the top off water in a way to get an accurate OG reading...

Brewers get a low reading if they get more of the top off water than the wort, conversely they get a higher number if they grabbed more of the extract than the top off water in their sample.

When I am doing an extract with grain recipe I make sure to stir for a minimum of 5 minutes (whipping up a froth to aerate as well) before I draw a grav sample and pitch my yeast....It really is an effort to integrate the wort with the top off water...This is a fairly common new brewer issue we get on here...unless you under or over topped off or the final volume for the kit was 5 gallons and you topped off to 5.5, then the issue, sorry to say, is "operator error"

More than likely your true OG is really what it's supposed to be. And it will mix itself fine during fermentation.

And just use the number it says in the instructions as the true OG, because it will be.

Ok, thank you for the advice! I did aerate the top off water and wort pretty well, but I may have over topped off.

To add one more bit to what Revvy said: after I pour from the kettle to the fermentor, I take a reading BEFORE I add any top-off water. Then I do the math and decide how much, if any, water I will add. I would rather have 4.75 gallons at the proper gravity, than 5.5 with a low OG. If the gravity is high, I calculate how much water it will take. But I don't bother taking another reading after topping off.

High-school algebra FTW!

frazier said:

To add one more bit to what Revvy said: after I pour from the kettle to the fermentor, I take a reading BEFORE I add any top-off water. Then I do the math and decide how much, if any, water I will add. I would rather have 4.75 gallons at the proper gravity, than 5.5 with a low OG. If the gravity is high, I calculate how much water it will take. But I don't bother taking another reading after topping off.

High-school algebra FTW!

Click to expand...

And if your not as "mathy" as Frazier, you can do the same thing with most brewing software. Just look for the dillution calculator or as I call it "Revvy's and idiot" button. (I'm mathematically challenged.Numbers make me woozy)