we found craft beer from tap had most of foam. I believe foam is the critical part of drinking experience. But I have one concerns, inject a shot of sonic similar to inject a shot of energy wave, by theory it should increase the temperature of beer. If not it is the best buy for beer drinker.
i was told by my customer from brewery, the reason we need foam for our beer and foam need to stay longer time is to prevent the beer oxidize.
i tested it and sounds to be true. same beer, both chilled but pour 1 with foam and 1 without foam. after keep for awhile, the one without foam taste differently.