June 2020

A ccording to consultancy firm BDO, Britain’s food and beverage sector – of which breweries form an important part – accounts for 19% of this country’s total manufacturing. Sadly, despite generating a combined annual turnover of £97.3 billion, food and drink manufacturers and processors don’t always see their high productivity reflected in large profits. One key issue that lowers their profitability is product recalls due to contamination. Recalling and disposing of contaminated stock is an expensive exercise whose costs may be compounded by reputational damage, compensation claims and loss of sales. Contaminants can make products unfit for consumption by spoiling their taste, appearance and colour, reducing their shelf life and compromising their hygiene. In a sector where the health of consumers and employees is protected by tight legislation and controls, this is a serious problem. Best compressed air practice Compressed air has many opportunities to come into contact with beer, other beverages and food products during their manufacture and processing, so it must be kept contaminant-free. Brewers use it, for example, to power machinery used in bottling, canning and kegging. There are various air-powered systems which handle, move and cool the beer, apply labels and secondary packaging, and help in the cleaning of brewery equipment. In processes like fermentation and aeration, there is particularly close contact between compressed air and the product. Food and drink companies should have Hazard Analysis and Critical Control Points (HACCP) plans in place which include measures to avoid contamination of compressed air. Specific guidance can be found in the publication ‘BCAS Food Grade Compressed Air Best Practice Guideline 102’. This sets out a voluntary code of practice agreed by the British Compressed Air Society (BCAS) and British Retail Consortium (BRC). It advises on the type of compressed air equipment to use and how it should be installed, maintained and audited. Recommendations on levels of air purity needed to minimise contamination risks from dirt, water, microorganisms and oil are also stated in the code. In addition, compressed air users are referred to international standard ISO 8573-1: 2010, which covers a range of contaminants and air purity classifications. Contaminants and their sources Contaminants in compressed air come from three main sources: the atmosphere, the compressor and the pipework through which compressed air is received and distributed. They may be present in three interacting forms: Solid – dust and microbes are drawn in from the atmosphere, while particles of various materials are released by abrasion or corrosion of the system’s components Liquid – along with compressor lubricants and coolants, the liquid contaminants include atmospheric water pulled into the system or condensing from vapour within it Gaseous – lubricants, coolants and water may all be vaporised Oil removal Oil contamination is especially unwelcome in brewing, as it kills yeast and adversely affects the beer’s frothing characteristics. Oil is present as hydrocarbon vapour in the air all around us, which we breathe and which we feed into our compressed air systems. Atmospheric hydrocarbons come from burning fossil fuels – in vehicle engines, for instance – and from Process, Controls & Plant Focus on: Compressed Air 20 | Plant & Works Engineering www.pwemag.co.uk June 2020 Clean air – clean beer Compressed air has critical roles to play in brewing operations but poses a major threat if it becomes contaminated. PWE reports.