Formula to pour the perfect pint revealed

Researchers studied which chemicals make the perfect foam on non-alcoholic beer, commercial beer and lager. Photo / Thinkstock

Pulling the perfect pint takes practice, but new research claims it may be less to do with technique and more to do with the exact balance of chemicals found in the beer itself.

Researchers studied which chemicals make up the head of a pint of non-alcoholic beer, commercial beer and lager - and more importantly, which combination of ingredients created the perfect height.

They concluded barley lipid transfer protein (LTP1), when mixed with intermediate levels of ethanol at lower pH levels improved the amount and quality of a drink's head.

But too much salt, as well as a chemical called dimethylformamide significantly reduced it.

The tests were conducted by students on Cornell University's College of Agriculture and Life Sciences course, The Science and Technology of Beer.

Bitter compounds found in hops, including iso-alpha acids, are important to brewers, said course tutor Professor Karl Siebert.

"Dissolved gases in the beer - carbon dioxide and, in some instances, nitrogen - play a role," said Professor Siebert.

"So do acidity, some ions, ethanol levels, viscosity and numerous other factors that have been tried by brewers and scientifically tested.

"But LTP1 is the key to perfect beer foam."

To discover the formula for the perfect pint, Siebert and his students placed different measurements of ovalbumin - a protein found in egg whites - iso-alpha acid, and ethanol in buffers of different pH. They were then mixed to form a foam, and a model foam height was created.

These tests discovered that intermediate ethanol levels create the best foam, while higher and lower ethanol levels produce a poorer foam. Increasing pH levels also reduces the thickness and quality of the head.

When ethanol was added to non-alcoholic beer, the effect on foam was similar to the model system. And when a lager was adjusted in pH, the foam increased with increasing pH.

Dimethyl formamide, dioxane, and NaCl solution were each added to the model system and beer.

Salt greatly reduced foam in the model system, while DMF caused the largest reduction in commercial beer foam.

Barley lipid transfer protein 1 (LTP1) and proteins Z4 and Z7 have long been associated with beer foam, and these tests found a higher level of LTP1 than the other two proteins in beer foam.

The findings will be published in Recent Discoveries in Beer Foam in the Journal of the American Society of Brewing Chemists.

"To some beer aficionados, the sign of a good head - the proper consistency, colour, height, duration - is to draw a face with your finger in the foam, before taking the first sip.

"If the face is still there, when the glass is drained and the liquid is gone - that's seriously good foam," continued Professor Siebert.

Pulling the perfect pint:

To discover the formula for the perfect pint, researchers placed different measurements of the protein ovalbumin, iso-alpha acid, and ethanol in buffers of different pH.

They were then mixed to form a foam, and a model foam height was created.

These tests discovered that intermediate ethanol levels create the best foam, while higher and lower ethanol levels produced a poorer foam.

Increasing pH levels also leads to poor foam.

When ethanol was added to non-alcoholic beer, the effect on foam was similar to the model system.

And when a lager was adjusted in pH, the foam increased with increasing pH.

Salt greatly reduced foam in the model system, while a chemical called dimethylformamide caused the largest reduction in commercial beer foam.

Barley lipid transfer protein 1 (LTP1) and proteins Z4 and Z7 have long been associated with beer foam and the tests found a higher level of LTP1 than the other two proteins in the model beer foam.

- Daily Mail