The world’s largest brewer is rolling out what it claims is a greener way to put bubbles in beer and reduce its CO2 emissions by 5%.

The Belgium-based company AB InBev says it has developed a technique to generate gas bubbles needed for the malting of grains before fermentation without the need to boil the water and hops.

The company conducted four years of tests at an experimental brewery in Leuven, east of Brussels, and then on a larger scale in two plants in the UK. The method it has developed does not detract from the taste of the finished drink, its says, while using less heat and water.

Bubbles are said to be crucial in determining the taste of a beer. Traditionally, gas bubbles in the early stages of brewing are generated via steam through the natural cooking process, requiring bountiful levels of water and heat. AB InBev says, however, it is able to simulate the effects of boiling the brew.

The new method involves heating the brew to below boiling point and then blowing nitrogen or CO2 into the tank to create bubbles without changing the taste. The company claims that because the beer is brewed at a lower temperature in the early phase, it can also stay fresh for longer. The bubbles found in the finished product are still to be produced in the normal way, typically by the yeast’s digestion of sugars or by pressurisation in the kegging process.

David De Schutter, the company’s research director for Europe, said: “Boiling and these gas bubbles are the sacred formula in the brewing process. Each brewer goes through a boiling process.

“Our innovation is to heat everything up to just below boiling point, which provides 80% energy savings at this point in time. There is a lot less steam released, which allows you to spend less on water. In our case, we managed to go from 5% evaporated water to less than 1%.”

AB InBev claims that when it has adopted the technique in all its breweries around the world it will reduce its global CO2 emissions by 5% a year, equivalent to the energy consumption of 120,000 families.

Studies suggest there will be 80% less evaporation as a result of a 0.5% reduction in water consumption, said to be “the equivalent of 1,200 Olympic swimming pools”.

The company, which hopes all its breweries will adopt the technique within 10 years, is offering to share the patented technology free of charge with smaller brewers.

A fee would be charged to the company’s larger rivals in the market. AB InBev has vowed to invest the money in further research to reduce its ecological footprint.