Issues with taking gravity readings from carboy . . .

I'm an extract brewer that typically ferments in buckets. I used by carboys for other things (mead, cider, apfelwein, etc.). But the carboys have been free, so I've fermented my last two batches in them.

The problem is that my SG readings have been significantly off from what was expected. Here's what I do, I put a couple gallons of cool water in the carboy. Then pour in the cooled wort. Then top off to the right volume. Give it a few swirls, and then take the SG (using a turkey baster) before I add the yeast. But the SG readings have been nearly 10 pts from what was expected. Considering these are extract brews, the expected gravity should be pretty spot on assuming the volume is close. So what gives? Is it possible that the brew is not fully mixed in the carboy and I'm only sampling the lighter stuff at the top?

I have not tasted a finished version of either brew, so I can't say whether they turn out OK or not. Thanks!

It's a pretty common issue for ANYONE using extract and then topping off with water (and that includes partial mashes)...It is actually nearly impossible to mix the wort and the top off water in a way to get an accurate OG reading...

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...

Don't sweat it..Just go by the OG in the recipe, as long as you made the correct batch size for your recipe (not for example making a 5.5 gallon batch out of a 5 gallon kit) You will nail the og....Extract recipes are actually fool proof. The OG in the instruction will be your OG give or take a not important point of two...

The wort and water will merge fine during fermentation.

StickyWicket said:

Is it possible that the brew is not fully mixed in the carboy and I'm only sampling the lighter stuff at the top?

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That's my guess. Think about how much stirring you (probably) did when you added the extract to the water initially. If you know the exact volumes, you can either take the SG of the "extract" portion and then calculate out how much it will drop when you add the remainder of the water, or stir the crud out of it. You can use one of the "wine whips" to mix it up, which will be good for aeration before you add the yeast, or just shake it up for a few minutes.

HomebrewJeff said:

If you know the exact volumes, you can either take the SG of the "extract" portion and then calculate out how much it will drop when you add the remainder of the water, or stir the crud out of it.

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?????? Never heard of anyone bothering with that....

No need to do that.....just go with the og in the recipe....it was caclulated for the right volume and Dillution...

If you altered the recipie by adding a booster pack would that increase the OG?

boydak said:

If you altered the recipie by adding a booster pack would that increase the OG?

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Yeah.....that's the point of booster packs. To "boost" the gravity.

Thanks for the knowledge! I suspected it was a mixing issue, but it's nice to know that other people encounter the same issue.

With a bucket, I can get in there and mix mix mix. But with the carboy, I typically aerate before I fill it up (basically, shaking the heck out of the water before I pour it in the carboy).

Go Tigers!

Back at this after 10 years (now that the plant I worked at is closed)
Did the same this afternoon. Now that the yeast is added would it hurt to stir it up and mix it a little better?

I started brewing (extract) about 8 months ago and I'm finding that my OG readings are much lower than expected also. I've suspected it's a mixing issue, and now it seems certain.

How do you get things sufficiently mixed in a carboy? Any handy home made tools that people like?