Laura Hadland looks into water use in UK breweries
Saturday 30 July 2022
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Water is one of the fundamental building blocks of life, and of beer. The brewing fame of Burton-Upon-Trent was built on the quality and composition of its water. But while it is endlessly fascinating, water as an ingredient is just a tiny part of the story.
In the UK, there is no legal requirement for water use to be capped; the law only governs waste products that need to be disposed of properly. But as consumers become more concerned with environmental issues, there is a strong commercial incentive alongside the moral imperative to reduce use where possible.
The most energy-hungry tasks in any brewery are heating the water to mashing in temperature, boiling the wort and then cooling it to fermentation temperature. Some of that energy can be reused if the steam is captured. An efficient heat exchanger condenses the steam as it quickly cools the wort. This clean, hot water created can be re-used for general tasks like mashing in, cleaning and rinsing.
The simplest ways for a brewery to reduce water use is to use a cooling tank, so that the water for cooling the wort is cold. It then takes less water to reduce the wort to fermentation temperature, but there is a trade off with the energy used to cool the water in the first place. Next brewers can ensure that the water used for cooling is fed back into the hot liquor tank for reuse, creating a relatively closed system.
At Purity Brewing Co in Warwickshire, a huge investment of £1.8million in 2012 paid for a brewkit that has “built-in mitigations against energy consumption,” the brewery’s John Conod tells me. “This includes heat capture technology so that in boiling no energy is lost. Instead the energy is recovered in the form of hot water, giving us an efficiency approaching 95%.” It also has a “clean in place” system installed in the brewkit, ensuring the absolute minimum amount of chemical cleaning agents and water are used.
It’s fair to say that most UK brewers are smaller than Purity, and would struggle to find the capital for this kind of investment. However, minimising water use is still a pressing issue. One of the UK’s newest commercial brewers is Libatory Brewing in Altrincham. It is solely run by Ian Holmes, who whips up 120l brews out of a freshly built log cabin in his garden.
Ian describes how being based in a residential area means that “it’s important we don’t cause any nuisance odour, so I use a condenser to capture the steam. This creates about 60-70 litres of water during a 1-hour boil that I collect in buckets. It’s nice and warm, so I use it to clean kegs, casks and fermenters, saving 30-50 litres of fresh water.”
At the other end of the brewing process, of course, both wastewater and solid waste count as trade effluent, so need to be disposed of properly. With the Environmental Audit Committee reporting this year that “only 14% of rivers in England can currently claim to have good ecological status,” this has never been more important.
It might be surprising that the run off from an organic-based process like brewing could harm the environment, but the water is low in pH and contains high levels of sugar and alcohol. Hydrogen sulfide gas in brewery wastewater can create corrosive sulfuric acid when it mixes with water vapour, damaging treatment vessels and pipes. Any solids that have not already been filtered out - spent grain and hop material for example - can turn into hard-to-treat sludge.
For most breweries, wastewater is taken away through the mains drainage under licence and it is cleaned at the local water treatment plant. However, in rural areas, there might not be any mains drainage or the local sewage treatment plant might be unequipped to accept it. This means the waste has to be manually hauled away, at the brewery’s expense.
A natural choice for sustainable water treatment is a managed wetland, including a reed bed. In the same way that a water treatment plant would pump oxygen into the water to aerate it, so the reeds pump oxygen down into their root zones. This allows the friendly bacteria in the water to do their thing and break down the pollutants.
Despite being a passive system, this is not a simple solution. Artificial wetlands require careful construction, management and maintenance over a large area. They require a permit from the Environment Agency, with all of the monitoring and risk assessment that entails, so hardly practical for an inner-city brewery knocking out gyles in a converted railway arch.
Purity has been using a natural passive wetland management system since it began brewing in 2005. John Conod describes this as “the largest and most impactful element in the early days.
“It is 4.5 acres of sloping ‘passive’ pond, plant and reedbed natural filtration. In general, breweries discharge their wastewater back into the drainage system. As industrial waste, the water companies impose a charge which can be up to three times what the water cost to bring in. We believe that a sustainable outlook is taking care of your own unwanted by-products rather than making them the responsibility of some other organisation.”
For reedbeds to work efficiently, most wastewater requires primary treatment to settle out the solids, moderate the temperature and possibly correct the pH. Purity does this by filtering out large solids and adding lime in a septic tank before it enters the wetland.
In Peterborough, Oakham Ales has installed a system costing around £100,000, which removes solid waste using filters, as well as adjusts the pH of wastewater before it goes to the foul water system. Oakham’s head brewer Mark Tetlow explains that “being located on an industrial estate, there is already a heavy loading on the main drains. It is important that we don’t add to the pressure on the system.”
Controlling output lowers the risk of Oakham being penalised by its water company for breaches of restrictions and lowers the cost per unit of wastewater overall. Even so, Oakham currently has no alternative but to send any sludge away for treatment. It is investigating greener options for the material, to see if it has any potential as fertiliser, for example.
With energy costs and other brewery overheads spiralling, increasing efficiency makes solid financial sense for breweries. However, the level of capital investment required to install the best green kit and technology can be prohibitive for smaller businesses. Instead, they make do, creating systems that are as efficient as possible within their own environment, like Ian at Libatory showed us.
How easy or cheap it is for a brewery to process wastewater on site changes according to its location. Rural, urban or industrial locations all present their own unique challenges. For us as consumers, perhaps the biggest responsibility is to do our own research and support the breweries that are making the most effort to minimise their footprint on the environment.
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