Low O.G.?

[brewdude25]

I just made an IPA and used 9 lbs Malt Extract. I figured it would come out around 1.060 or higher. The O.G ended up being 1.052. That seems pretty low for 9lbs of extract. Anyone have any ideas why it would read so low?

 

[nebben]

5G batch? 10G? Did you do a partial boil and add water at the end?

If 5G and partial boil, I would bet you didn't mix them adequately before you took the measurement.

 

[944play]

If 5G and partial boil, I would bet you didn't mix them adequately before you took the measurement.

+1. Almost certainly this is the case, but far less likely things to check for:
Gravity reading taken at hydrometer's calibration temperature?
Volume measurement calibrated?
Extract potential and weight verified?
No spills, boilovers, or racking losses?

 

[brewdude25]

It was 5g. I dont know what partial boil is. I boiled for 60 minutes then added about 3.5 gallons to the carboy to get it up to the 5G mark. I only swirled it around for a couple seconds before I took the reading. So that is probably it. Damn!

 

[Revvy]

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 OG is really what it's supposed to be.

 

[brewdude25]

Thanks guys. That makes much more sense to take the reading AFTER I aerate. Don't know why I did it before this time. Now I'll just have to settle with not know the ABV.

 

[a10t2]

I think your best option is actually to take the reading before adding the water, then calculate the OG based on how much you'll be diluting the wort.

But if you're brewing with extract, there's really no need to take an OG reading at all - as long as the weights and volumes are measured accurately, you can just calculate it. 9 lb of LME in 5 gal is 1.067, for DME it would be 1.077.

 

[nilo]

Some quick calculations to show how much the final volume of your wort can affect your OG.
For 9lb of LME, volume target=5.0 gals:
4.5 gals => OG=1.080
4.8 gals => OG=1.070
5 gals => OG= 1.065
5.2 gals => OG= 1.060
5.5 gals => OG=1.054

That been said, I believe that measuring incorrectly the final volume is the most common cause of missing the target OG.

 

[944play]

4.5 gals => OG=1.080
4.8 gals => OG=1.070
5 gals => OG= 1.065
5.2 gals => OG= 1.060
5.5 gals => OG=1.054

Those sound off. Here's what I get, for 37 ppppg extract:
9 x 37 = 333 gravity points
333 / 4.5 = 74 gp/gallon or 1.074
333 / 4.8 = 1.069
333 / 5 = 1.066
333 / 5.2 = 1.064
333 / 5.5 = 1.061

 

[nilo]

Those sound off. Here's what I get, for 37 ppppg extract:
9 x 37 = 333 gravity points
333 / 4.5 = 74 gp/gallon or 1.074
333 / 4.8 = 1.069
333 / 5 = 1.066
333 / 5.2 = 1.064
333 / 5.5 = 1.061

Your numbers are correct. Thanks for catching that.