A recent study on beer foam introduced a lot of people to a strange type of science: brewing research by non-brewers. I first came across this genre in a previous job when a study into brewing with bread crumbs was published. The draft had some right bollocks in it about how increasing fermentation temperature increases alcohol yield, which I was uncharitably blunt about. Looking at the paper I see it still made it into the published version so I guess they didn't take it to heart, or indeed listen to a bleedin' word I said.
With a limited understanding of the brewing process it is likely that confusion will creep in, or indeed stomp in and trample all over your work. This has certainly happened with the foam paper, as the chorus of derision from brewers about how many times beers are fermented testified. The authors' misunderstanding about single, double and triple fermentation seems to have obscured the very obvious difference in the beers they studied: some are bottle conditioned, so undergo a secondary fermentation in the bottle, and some are not.
In the world of brewing those that have been seduced by Satan commonly defend the diabolical practice of using extraneous CO2 to carbonate beer by saying that CO2 is CO2 wherever it comes from. Now I'm sure that a CO2 molecule coming from a gas bottle is the same as a CO2 molecule produced as god intended by fermentation in the container from which the beer is served. But this is not to say the bubbles are the same and surely even Satan's minions will have noticed that foam you get from bottle conditioned beers is different from the foam you get from artificially carbonated beers.
Surprisingly, seeing as generally winemakers are a primitive bunch, I did once read a very interesting book on bubbles in champagne. For those not aware, champagne is bottle conditioned, with the yeast subsequently removed by riddling and disgorgement. If I remember rightly, the author put the fine bubbles of champagne down to nucleation sites from yeast fragments. It would be good to have more research into bubbles in beer, as it would provide a rare instance when science backs up the faithful.
The authors of the beer foam paper appear to be competent scientists, even if they are ignorant when it comes to brewing. They certainly seem to know a lot about the science of bubbles (Marangoni stresses is a new one to me!). And they correctly discuss Lipid Transfer Protein 1 as playing a key role in stabilising foam, though this nothing new to brewers. In fact last year I went to a talk by "The pope of foam" Charlie Bamforth where he discussed the role of Lipid Transfer Protein and Protein Z (40 kDa) in foam stability. He said research had shown this was not due to any particular property of the proteins, but rather that the partial denaturing of them during the boil (not during secondary fermentation!) exposed their hydrophobic interior which helps stabilise bubbles.
My humble suggestion for people not from a brewing background planning to publish research into beer is to talk to a technical brewer first. It would be beneficial to all.
