Preet Singh, microbiologist at McGargles, gives his insight into some of the scientific methods applied in the brewing process.

Having just completed my degree in Bio-Technology at Maynooth University, I consider myself very lucky to now be working here at McGargles, as one of the resident microbiologists. While at college, I never really considered pursuing a career in the food or drink industry but I’m delighted to be a part of such a new enterprise. Each day is an educational experience and it has been exciting seeing how a company grows from within.

My main role here is to propagate and maintain our onsite yeast. We’ve just embarked on a new and ambitious project in our yeast production. Initially, I was growing just 2L of yeast for our small fermenters twice a week. But now, starting with a vile of active yeast, we are producing from 2L right up to 32L, so it can be utilised in our entire production plan. When possible, we take the yeast from one batch and use it in another fermenter. This is achieved by giving any remaining viable yeast enough nutrients so it will multiply to the required level for our production process.

Yeast is a reproductive organism which, over time, progressively divides into sets of two cells. Some of the yeast we bring in from labs would be the ‘children’ from an original cell line that has been in storage for decades. We only use yeast for a limited amount of generations, and I must ensure that it is consistently of the highest quality and purity.

Yeast must be carefully propagated because it has no immune system or barriers, so it can take something as little as a person breathing on it to cause an infection. We also have to avoid any mutations in the yeast because it can result in a different flavour profile in the beer. The same can be said if there is any dead yeast present, which is not harmful, but it does omit very sour flavours.

In addition, I frequently test for unwanted by-products which may occur during the fermentation process. Most notably diacetyl, which is liked in some beer but not in ours, because it gives a very slippery after-taste, like buttered popcorn. To detect for the presence of that, I did some research on sensory testing by tasting or smelling to accentuate its presence.

Assisting in the process of making sure that our standards of production are in line with British Retail Consortium (BRC) has recently been added to my list of duties. Many in the food and drink production industry are certified by the BRC because it signifies to potential clients that your company adheres to the most stringent procedures.

Our head brewer, Alex Lawes, has been instructing me on Hazard Analysis Control Points (HACP), which is a topic that was extensively covered during my degree. We have to vigorously monitor all our vessels, pipelines and containers so that they are completely sanitised because once a mash is in production it becomes a closed environment