Aeration with airstone...when to do it?

So I recently brewed a batch of american red ale last night, and I missed my OG by several points. Target was 1.060, and i ended up with 1.046. Part of the reason was i used to much sparge water, and ended up with about .8 gallons too much wort.

I realize (now) that I could have boiled some water off, but i had already added my hops and I didn't want to ruin my hop profile. So my 5 gal batch turned into a 5.8 gal batch.

Anyway, I also used an airstone w/ aquarium pump and inline filter to aerate my wort before siphoning to the fermenter. There was a crap ton of foam in my brew kettle from doing this. So my question is....should I have aerated in my carboy instead of in the brew kettle? Isn't all that foam made out of sugars that should still be in my beer? I'm wondering if the reason my OG was so low is because I left behind all of that foam in my brew kettle.

The foam is no more or less concentrated than the rest of the beer. Sugars don't separate out like that. If it's convenient for you to aerate in the kettle, that's fine and dandy.

Yea i aerate while the wort chiller is running..buthe foam has to be made out of something...its not just water and air. But maybe you're right, maybe its negligible.

You think the difference in OG is purely because of the larger batch size?

FishNChips said:

Yea i aerate while the wort chiller is running..buthe foam has to be made out of something...its not just water and air. But maybe you're right, maybe its negligible.

You think the difference in OG is purely because of the larger batch size?

Click to expand...

It is made out of something...it's made out of wort. There's sugar in the foam, but there's also water. Gravity is essentially a reading of the ratio of sugar to water. Excess foam will cost you volume, but it won't selectively pull the sugars out of solution to change your gravity.

A 5 gallon 1.060 batch would be 1.052 at 5.8 gallons. That accounts for a significant chunk of your disparity, but not all of it.

Ok - right i got ya, that makes total sense.

Hmm..ok well i will have to examine my process and see what else might be causing the drop in OG. Thanks MalFet