A beer’s foamy head is more than simple presentation.  A beer’s head is intrinsic to the drinking experience, it’s part art and part science and it doesn’t happen accidentally…

And now researchers in Japan have found that a hearty beer head increases a beer’s flavor.

Here’s the deal…

When beer is poured, the trapped carbon dioxide forms bubbles, creating that familiar, inviting layer of foam that we call the beer’s head. But a beer head is much more than decoration. Each time a bubble bursts, it releases aromatic particles that enhance your beer’s smell, as well as its taste.

The study, which was conducted by researchers from Kyushu Sangyo University in Fukuoka, Japan as well as by the Japanese brewing company Asahi, highlighted how bubbles in the beer trap flavor compounds that are amplified when those bubbles are released into the air near the drinker’s nose.

According to the study: “The foam acts as an efficient gas exchange surface funneling aromas toward the drinker’s olfactory sensors, and it provides a drinker’s first tantalizing entrée as to the quality of the beer’s flavor, freshness, and wholesomeness.”

And beer heads differ.  Different types of beer produce different levels of foam, all tempered by the brewing process and the brew’s ingredients.

The key to a beer’s ability to generate foam and retain carbonation lies in its mix. Barley, hops and wheat contain a certain type of protein which is highly “hydrophobic.” Hydrophobic means that it repels water which also happens to be the #1 ingredient in beer.

These repelled proteins then attach themselves to the C0₂ bubbles, creating a coating around them and ride them to the top of the brew creating a layer of frothy foam.

Hoppy beers tend to deliver stronger heads with thicker and more stable foam, but other factors can also impact the quality of a beer’s head.

Beers with a higher alcohol content tend to have less foam, as alcohol tends to break it down. And the cleanliness of the beer’s glassware can also impact a beer’s head. Residual oils (whether on a glass or your finger) can quickly break down the quality of a beer’s head.

The research, which was published in the Journal of the American Society of Brewing Chemists, also found that a big beer head can also serve a “lid” for carbon dioxide, locking in flavors that might be impacted by its exposure to air.