A carbon footprint calculator has been developed by a research team to help small craft brewers gauge the scale of their carbon emissions.

Piglove carbon calculator
Prof Nik Watson (left) and Dr Alex Bowler (right), from the School of Nutrition and Science at Leeds University, with Marcos Ramirez at Piglove Brewery. Photograph: Victor De Jesus

Created by a team led by the University of Leeds, the freely available calculator — which can be downloaded as an Excel document from the figshare website — will enable breweries to see how sustainable their operations are.

There is a wide variation in the carbon emissions produced by craft brewers, with packaging playing a key role. Beer distributed in 20-litre steel kegs has a carbon footprint seven times smaller than that distributed in 330ml glass bottles — 205 versus 1,483 grams of CO2 equivalent per litre of beer.

With independent brewers showing signs of bouncing back after lockdown, the researchers are keen to help these small to medium-sized enterprises develop best practice when it comes to sustainability and cutting carbon emissions.

The research paper accompanying the carbon calculator — Development of an Open-Source Carbon Footprint Calculator for the UK Craft Brewing Value Chain — has been published in the Journal of Cleaner Production.

For small brewers, sourcing the key facts and figures needed to calculate their carbon footprint is both expensive and technically challenging, and can require the use of proprietary software.

Alexander Bowler, a researcher at the School of Food Science and Nutrition, in Leeds, in collaboration with researchers at the universities of Nottingham and Sheffield, has created an open-source calculator which will guide brewery managers through the process, simply, and at no cost.

Baseline data ‘hard-wired’ into the calculator will enable brewery managers to estimate carbon emissions across the entire production process, from growing and sourcing raw ingredients to producing and transporting the beer. The way the beer is packaged, which can have a big effect on carbon emissions, is taken into account.

“When a small brewery is doing its carbon reporting, one of the challenges is finding a lot of the numbers you need to use,” said Dr Bowler.

“For example, transport emissions or emissions associated with energy usage are quite easy to source, but there are lots of other data to do with materials, such as hops and barley, that are harder to find.

“You need these numbers and specialist conversion factors, and we have got them all in the carbon footprint calculator from reference sources.”

Brewery staff input their production data into the calculator, and the calculator produces a figure for overall carbon emissions with a breakdown for different stages of the value chain.

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Marcos Ramirez runs the Piglove Brewing Co, in Leeds, with two colleagues, which produces 12,000 litres – just over 21,000 pints – of beer a month. He said the calculator would improve the accuracy of the estimates of his brewery’s carbon emissions.

“As a business, we have a responsibility to society to reduce our carbon footprint, but we operate in a niche market and finding the baseline data to calculate carbon emissions is challenging,” he said.

“There are a lot of tools that can be applied more generally, but nothing to help with very specialised industries, like brewing, where often the baseline data we have had to rely on comes from the US — and that introduces inaccuracies into our calculations. So, this new calculator will be a major improvement.”

Professor Nik Watson, also from the School of Nutrition and Science, who oversaw the research, said once small breweries have a picture of their carbon emissions, they can then look at ways of reducing them, and that will have wider sustainability benefits.

His team is working with the Piglove Brewery to identify how low-cost sensors can be used to measure the efficiency of parts of the production process such as water use, energy consumption, and minimising waste.

They are also using a probe based on the principle of a tuning fork to measure the resonance and, hence, the density of wort in the fermentation vessels, to judge whether the beer is ready to package. The sensor is part of a cloud-based technology developed by a company called Plaato that sends data to a mobile phone.

Prof Watson said: “These are small businesses, and they cannot afford the high-end sensors that the large breweries use. But there are other, smaller smart instruments that can be harnessed.

“By working with breweries, we can show that sensors can provide real data and that can help them with decisions about changes to production processes or raw materials to reduce carbon emissions and improve sustainability.

“This real data will show how various interventions are working. Many people involved in the craft brewing industries are natural innovators and they want to make their operations as green as possible.”