Recirculation and head retention

I've had low to moderate head retention with my beers recently, and I've been trying to figure out why. I'm not using any soaps or anything that would kill the head, so I'm a bit baffled.

One thing I do is to recirculate the mash runnings before sparging, for a good 10-15 minutes until the wort is crystal clear in the sight tube.

I'm wondering if I've been stripping too much protein out of the wort by doing this, and it's preventing head retention?

Thoughts?

MC

No, I can't imagine vorlauf having anything to do with that. Most commercial breweries will vorlauf for 30 minutes... some even through the duration of a mash.

No, I can't imagine that would have anything to do with head retention. I recirculate too (I have a HERMS) and I have clear wort and great head retention.

A couple of things come to mind. One is a too-long protein rest. But if you're not doing a protein rest, never mind that one.

One possibility is recipe- recipes with crystal malts and/or lots of hops just have better head retention. Although I have a Fizzy Yellow Beer recipe with NO crystal or wheat and low hops and it does have good head retention, so it's not always true that you "need" carapils or wheat for good head.

Is it possible that you've added something, like Fermcap-S, to your process or another silicone/oil component that would have an impact that you're just not thinking of?

A friend told me that he noticed that burst force carbing his kegs (by shaking the keg) did a number on his foam and retention. That could be a possibility I guess, if you're doing something like that but that would be unusual.

Are you getting a nice hard rolling boil with a good hot break? And quick chilling with a good cold break? Any whirlfloc or Irish moss in the boil? Are you using gelatin for clarity?

The only thing I use is Irish moss, 2 teaspoons per 10.5 gal batch. The hot break is fine (sometimes even massive chunks when using German pilsener malt). Beer clarity is excellent.

Most of my beers use some crystal, or cara-pils, sometimes wheat. Strong boil (I lose 2.5 gallons per hour of boil), carbonation is done "set it and forget it", takes about 10-14 days, I've noticed paler (less crystal) beers take more time to carbonate - I have a Helles that's just mildly carbonated at 3 weeks.

I do use silicone hoses but no silicone products anywhere else. No gelatin.

Fermentation "appearance" hasn't changed at all.

MC

Another thread I just read reminded me of an article I read a while ago that is also relevant to this thread. I pulled it up and re-read it (quick read)

A copy can be found here: (nice article, not toooo technical)

The foaming properties of proteins isolated from barley
Gregory R Kapp and Charles W Bamforth

A couple things they said that might provide some clues to your problem:

Has your boil changed? A good boil is needrd to convert some of the proteins into a more foam positive form.

Any change in your hopping? The iso alpha acids promote foam stabilization, so the more bittering additions the more foam stability.

Any possible pH issues? Are you for some reason getting less of the hordein fraction in your wort?

Have the beers sat for a long time on the yeast cake, or possibly undergone any kind of stress?

Here is the final sentence from the paper:

Both protein fractions are susceptible to hydrolysis by the proteinase A from yeast, resulting in diminished foam stability and highlighting the justification for limiting the contact of beer with deteriorating yeast.

Click to expand...

I like this last quote - from Bamforth no less. Now the question is what qualifies as deteriorating yeast?