Food scientist and writer Dr Stuart Farrimond set out to establish the perfect pour technique and serving temperature.
Following his research he explained that the key to pouring is the bubbles in beer. Unlink other drinks the bubbles have a rough skin due to surfactant molecules – which reduce the liquid’s surface tension.
The bubbles are large and rise slowly, with a unique structure which accommodates the beer’s flavour.
Dr Farrimond claims that pouring at more than 15 degrees from a bottle ruins the flavour, due to rapid bubble formation.
The scientist’s research concluded that the traditional 45 degree angle is only appropriate for long taps.
When pouring a beer it is key to ensure beer doesn’t hit the glass too fast. Otherwise there are too many nucleation sites – which enable the separation of liquid and gas.
That’s why the further the glass from the beer, the more bubbles are made, leaving a larger head and the flatter and blander the beer.
Dr Farrimond experimented with different glasses and full 500ml bottles of beer. It won’t be any surprise to anyone who’s pulled a pint that nucleation sites dropped as the angle became more horizontal, dropping the head of the beer.
Also on the agenda was optimum temperature. Farrimond claims only slight changes have a profound effect on flavour. Lower temperatures can inhibit tastes coming through.
The balance must be found between temperatures – with cooler drinks often perceived as more refreshing – while protecting flavours.
He concluded pale ales and lagers should not be served below 5⁰C, whereas other ‘craft’ beers should be at 20⁰C – near room temperature.
He found optimum temperatures for other English ales to be 18.5⁰C for medium, 21⁰C for dark and 20⁰C for a stout.
The research was carried out in preparation for Ascot Racecourse’s Autumn Racing Weekend and CAMRA Beer Festival.