[diholuxi]

A couple of the beers I've brewed over the past few months have ended up with these really beautiful, persistent creamy heads -- almost as fine (fine, as in minuscule bubbles) as a nitrogen beer.

I realize the chemistry and physics of head composition is complex, but I'm wondering if anyone has any ideas on how to replicate this?

The two beers were an amber ale and a pale German lager, so I can assume it's not related to yeast strain, fermentation temperatures/times, or grain bills. I use irish moss in the boil, fine with gelatin and burst carbonate in kegs.

I usually leave my beers under a constant 8-10 psi for serving, and the heads seem to get progressively 'finer' over time, perhaps it has something to do with CO2 becoming less soluble, etc?

https://lewdharry.com/

[Ellismr]

It is driven in part by wort chemistry, process techniques, and  carbonation levels.  In short there is no simple answer but I have found that keeping detailed notes of your process while brewing the same beer will help in perfecting the product you want.  I find that us homebrewers can be harder on ourselves in comparison to the commercial brews we are trying to emulate.  I.E. I'm a pilsner fan.  I can buy Warsteiner Premium German Pils and the head out of the bottle is never dense or long lasting compared to what I make here at home.  IMHO that is what happens to beer as it ages.  The pils in question was 90 days into the package.  My pils never lasts more than a few weeks. 

Back to process data:  The data I gather is Mash Ph, Pre-boil Ph, and knock out Ph along with pre-boil and knock out gravities.  Finings used and qty.  This is in addition to all the recipe composition data that I have in Beersmith.   Protein composition of the grain has an impact on head formation and retention as well and as a homebrewer we will never get a cert of analysis for the grain we buy.  The shop that sell the grain only have general or average information.

If you want to go down the rabbit hole you can find books written by Dr. Charlie Bamforth on the subject.  Cheers!

[BrewBama]

One thing to notice about beer foam that I rarely read about: watch how a beer is poured.

I’ve seen some tilt the glass until the beer is all the way to the top — at the rim — then slowly bring it upright as the liquid comes to the top of the rim. The goal is to prevent a glass full of foam. However, this type pour keeps the CO2 in the beer and the drinker gets a belly full of gas.

But when you see a beer with a big head poured you see that it’s poured at an angle but fairly aggressively closer through the middle of the glass in an effort to create some foam. Then at about the 2/3 point the pour is stopped and the glass set aside for a few moments. This rest allows the foam on top to condense and dry. Then, the beer pour is continued with the glass straight up and aggressively to the government line with the foam sitting like a crown above the line and even the rim of the glass. This pour breaks some of the CO2 out of solution creating the foam. The drinker doesn’t feel so full from gas. ...and will have another beer. $

Of course, mash rests aid in foam, ingredients with protein help foam and so on. But the bartender has a role as well.


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[denny]

Could be due to differing protein levels in the malts

[Northern_Brewer]

The drinker doesn’t feel so full from gas. ...and will have another beer. $

Or you have a cellarman who can set the pressures correctly on the keg lines.

Or just serve cask-conditioned....

It's not just the pour though - glass cleaning is a significant factor, as well as all the usual brew-ery things like protein content, modification of the malt and so on.

[hopfenundmalz]

The foam Is CO2 trapped in a film of proteins and hop oils. Glycerol from the yeast can also be foam positive.

There was a good presentation about foam at HomebrewCon about 4-5 years ago, but it never got to the website. This is informative too. It does mention growing conditions having an influence.

https://www.craftbeer.com/craft-beer-muses/the-science-behind-beer-foam

[Die Beerery]

My thoughts on foam.

http://www.lowoxygenbrewing.com/uncategorized/foam/

[goose]

My thoughts on foam.

http://www.lowoxygenbrewing.com/uncategorized/foam/

A good read.  I just skimmed it and will need to a more in depth reading of the article.