No foam from all-grain aeration.

My last two batches have been my first all-grain batches. I always use carboy shaking for 5 minutes to aerate the chilled wort before adding yeast. Before going all-grain, the shaking generated a ~6 inch foam on the top of the wort. In these two all-grain batches, there was less than an inch of foam. Both beers are medium gravity ales (~1.050 OG). Also, these two beers are both SMaSHes, so I had no specialty grains for head retention.

1) Should I be concerned about not having aerated enough, or is the foam head a poor indicator of aeration?

2) Why is there less foam? Is this common with all-grain as opposed to extract, or is it more likely a result of the lack of head benefiting specialty grains? Something else?

3) I also noticed that the krausen was very thin, although the fermentation otherwise appeared to be quick and vigorous. Is this related to the lack of foam?

Could be. I have a couple of ideas, but any definitive answer is dependent on a multitude of factors.

Recipes and procedures. That's what we need. Before we can pinpoint a culprit, we need a suspect list.

Bob

+1 to the above. There a few things it could be, but we need to know your recipe and process to be able to help.

Recipe #1:

5 gallons post boil
10# Munich
1 oz. Mt. Hood @ 60
1 oz. Mt Hood @ 20
1 oz. Mt Hood @ 0

60 minute stovetop mash @ 155
30 minute stovetop sparge @ 170

Recipe #2:

5 gallons post boil
10# Maris Otter
1 oz. EKG @ 60
1 oz. EKG @ 20
1 oz. EKG @ 0

60 minute stovetop mash @ 155
30 minute stovetop sparge @ 170

Did you bottle yet??

RedIrocZ-28 said:

Did you bottle yet??

Click to expand...

No, but I'll probably be kegging the first one in about a week.

RDWHAHB. Diagnosing a problem with your beer while still in the wort phase is like trying to find the cause of a problem that hasn't happened yet.

While I have never made a SMaSH recipe, I could only guess that the lack of specialty grains will lead to less head retention in the finished product. But I never thought that how much foam you can make in the carboy had anything to do with the final head retention of the beer. ..

I'm not really worried about the end result being bad, but I'm still curious as to why there was no foam.

I would think that the same kinds of compounds that cause a head to form would also cause aeration foam to form. In either case, there's something in the liquid that makes it, for lack of a better word, "stickier" and keeps the bubbles from popping easily. My hydrometer sample tasted normal and had a typical mouthfeel.

Would solid bits of grain or break material that I wasn't able to keep out of the fermenter get in the way of generating a foam? I siphoned into the fermenter, and I didn't do a good job of whirlpooling, so there were visible bits of solid stuff in the fermenter.

Hmm... you ever try to blow bubbles with the little wand in the "bottle of bubbles" as a kid after you dropped it in the dirt? Surface tension is interrupted by the bits of dirt on the wand, in much the same way I would think floating debris would hamper the bubbles in your aerated wort.

Sounds like a sound hypothesis anyway.

I wouldn't be too concerned about not using speciality grains for foam - standard malts still give plenty of head forming molecules as most loss of foam comes from anti-foam entities. Foam is made by hydrophobic proteins, these can be broken down in mashing or stick to the inside of your boiler when you transfer to your FV, but generally enough remain to give decent head. Detergents, rinse aids and especially fabric softener residues kill head so don't let them near your kit. But like these other guys have said wait until the beer's finished before you draw any conclusions.