Diary of a Brewer: Trial Week Part 1

Link to Diary of a Brewer: Preface

So when I first came up with the idea of journaling my trial week at BrewDog I had intended on writing an entry after each shift. Unfortunately one of the first things I learned about being a brewer is that time is valuable and more often than not your only free time is spent sleeping in preparation for your next shift. So instead of this entry describing my first shift it will be describing my first three.

My first shifted started on Monday afternoon at 14:00 and was busier than I imagined. At the moment BrewDog runs a system comprising of a hot water tank (~70 hectolitres) a mash tun (~50 hl) and a copper (~65 hl) as well as 23 fermentation vessels (FV) ranging from 50-200hl; A fairly standard system for any brewery. When I arrived the contents of the copper had just been fed into one of the FVs and so my first job was to clean the inside of the copper in preparation for the next brew. This involved climbing into the copper and scrubbing the walls and coils to remove the residue from the previous boil. The copper that BrewDog uses is powered by a large pipe about 15cm in diameter that is filled with burning gas during the boil; I can only assume this method is used because it is the most cost efficient way to boil 5000 litres of wort. After cleaning and reassembling the copper it was time to prepare the next brew.

Because of the high demand for BrewDog beers, coupled with the fact that they have only one brew system to supply 23 FVs, the brewery never sleeps. When one brew is finished the next batch of ingredients is laid out and as soon as the mash tun and copper are clean the next brew is started. My second task was to mash-in on a batch of Dogma. Mashing-in is the first stage in the brewing process where malt (grains) and water are fed into the mash tun at a carefully controlled rate. The grains are left to soak in water that is heated to between 64-70C depending on the recipe being used. During this process the fermentable sugars contained in the malt are released into the wort. The recipe that we were using for Dogma called for ~1100kg of grains that were fed in 25kg bags into a pump that mixed them with water and carried them into the mash tun. After 105 minutes of soaking the grains we began transferring the wort into the copper.

The transfer of the wort from the mash tun to the copper takes about three hours. The transfer is done this slowly because of the manner in which the grains distributed in the tun. When the grains are soaking in the mash tun they are mixed with water in a ratio of 2.5ml/g, a ratio that maximises the efficiency of sugar extraction while minimising the volume of the mash. The grains are suspended in the water and when the transfer begins further water (heated to about 80C) will be added to the mash tun very slowly in a process called German sparging, while at the same time water is drawn out the bottom of the tun at a slow rate. The process is done slowly to maximise the amount of time that the water is in contact with the grains and the rate at which the water is carried out of the tank must very closely match the rate it is fed in. If water is drawn out of the tank too quickly it can cause the grains to compact against the bottom of the mash tun and the mash will become stuck.

Four times during the three hour transfer samples of the wort are drawn off and cooled. We then measure the temperature, pH, gravity and total volume of the copper at each stage. The gravity of the wort is a measure of how much fermentable sugar is dissolved in the liquid, and is measured using a hydrometer. A hydrometer looks like a thermometer with a weighted bulb on the end and when submerged it will find a buoyancy point that depends on the density of the wort. The hydrometer reading is adjusted based on the temperature of the wort and this value allows us to determine if the post-fermented beer will have the alcohol content that we are aiming for. Once the transfer is finished the copper is set to boil for an hour. All in all, the above process took the duration of my shift on Monday (until 22:00), and I packed up for the day just as the finished wort was being sent through a heat exchanger for its transfer into a FV.

After my shift I sat down in the staff area with a few of the other employees from the bottling line. BrewDog hooks up a kegerator for the staff to use once they have finished their shift and I enjoyed a fantastic pint of Imperial Lager; a beer that I only found out after my pint was 9.9%. It made a brilliant night-cap, and I managed to stumble home for a few hours’ sleep before staring at 5:45 the next morning.

After a terrible 4 hours’ sleep I woke at 5:10 on Tuesday morning feeling like I had been hit by a train, a feeling that has not subsided yet. Arriving at the brewery at 5:45 I walked in just in time to mash in for the second time, this time on a batch of Hardcore IPA. And so by 6:30 in the morning I had already lifted 1300kg. Once we mashed I started a rota of ‘tank-actions’. Tank actions are several different jobs that need to be carried out on fermenting beer to ensure its quality after fermentation. They involve de-yeasting, de-hopping, and rousing. Because the FVs are so large fermentation that would normally produce small amounts of dead yeast and enzymes produce several hundred litres a day (I took 1050 litres of yeast out of a 200hl tank). This sludge from the bottom of the tanks needs removed at regular intervals so the beer is semi-clear when it comes time to filter and bottle it; this is de-yeasting and de-hopping. Rousing involves pumping CO₂ into the tanks of beer for 2 minutes to do just that; ‘rouse’ the beer.

After the tank actions were finished the mash tun used for the Hardcore IPA was ready to be emptied. At very large breweries this is an automated system, but at BrewDog cleaning the mash tun involves climbing inside it and shovelling out the spent grains. Because of the high specific heat capacity of water (4.18 Jg^-1K^-1 compared to 1 Jg^-1K^-1 for Air and 0.45 Jg^-1K^-1 for Iron) the moisture remaining in the grain had not cooled much from the temperature of the mash and sparge liquor. I stand by the statement that I have never been so hot as when shovelling ~1500kg of damp grain in temperatures ~65-80C (149-176F).

Today passed much like the previous two days. I arrived this morning, again at 5:45, just after the night shift had mashed in on another batch of Hardcore IPA. So I completed the tank actions and waited to shovel out the mash tun again. The last thing I did before I sat down for a pint of Hardcore IPA this afternoon was to prepare the bags of malt for a batch of Black Ginger to be mashed in by the afternoon shift.

I’ve been passing the time (when I am not at work and not sleeping) at ‘The Elizabethan’, a pub located a 5 minute walk from the B&B chatting with the bartender about starting work at the brewery;  A very nice man who just brought me a pint of Punk IPA as a welcome to Fraserburgh.  

It’s a quiet town, and bloody hard work, but I’m enjoying every minute of it.

Link to Diary of a Brewer: Trial Week Part 2

Diary of a Brewer: Preface

Less than a week ago I sat my very last exam at the University of St. Andrews. An exam whose simple title of 'Stars' was anything but appropriate to describe the complexity of the course content. since I received no communication from the university to arrange a re-sit I can only assume that the marks were of passing quality and I must now only wait until the graduation ceremony on the 20th of June to receive my BSc in Astrophysics.

Naturally one would assume that once gaining such a degree that I would seek work in a relevant industry. For some reason everyone thinks I want to work at NASA or CERN, or that I will pursue a Masters degree. Yet to everyone's surprise (including my own to a certain degree) I applied for a job at BrewDog, a Scottish brewery located 118 miles north of Edinburgh in Fraserburgh Scotland. This decision may seem strange for someone who has just finished my degree, but my interest in beer and its production is not a new fascination.

In the summer in-between my second and third year of university I became interested in beer production and so had a friend of mine (Pete McKale) order me a home brewing kit through his paypal, for which he was reimbursed. At first I started like nearly every home brewer does and made several brews using kits of pre-mashed ingredients that simply needed to be diluted with water and pitched with yeast. Needless to say the results were anything but amazing. These kits often contain ingredients of questionable quality and the yeast is almost never fresh; tending  to produce brews that are very light in colour and flavour. I carried on in this manner for several months until I received a phone call from another friend (Susan McCulloch) in December of 2010 who told me a pub in town that had recently closed down needed some help with renovation before they reopened. I spent nearly every waking moment helping get the pub ready to open over the course of 3 weeks and at the end I was offered my first bar shift as a thank you on New Years Eve 2010. The pub was 'Aikmans' where I have work 2 shifts a week ever since. A pub that specialised in German and Belgian beers as well as the owners love for real ale. Through this job I became more and more familiar with the techniques of beer production. So during the summer of 2011 I researched how to brew using a method called extract brewing, this is where the cereal grains are ordered pre-kilned and I would prepare the mash myself using a combination of cereal grains, malt extract and actual hop cones. I ordered 140 litres worth of brewing tanks and started production of beer on a bigger and better scale.

It was once I reached this stage that I truly became fascinated with brewing. While researching this method of production it amazed me how many variables there were when it came to beer production and how much control (or sometimes lack of control) you can have on the taste of the final product. I continued on in this manner until the spring of 2012 when I heard about a brewery opening near St. Andrews by a local beer enthusiast named Bob Phaff. The Saint Andrews Brewing Company  opened in January of 2012 and Bob has turned his passion for beers into business based in Glenrothes with plans to move the brewery to St Andrews sometime in the near future. When I heard about the opening of a brewery I sent Bob an email asking him if he needed any help. And so in early April I spent a few days with Bob brewing and bottling a few thousand beers at his brewery. At this point I was hooked.

After my visit to the St Andrews Brewing Company I searched frantically on-line for brewing positions and saw a job offering for an Assistant Brewer on BrewDogs website. And 36 hours after my second application I received an email inviting me for a trial week and interview. I asked Jenny to search the Internet and find me a beer brewing textbook and she managed to find me 'Brewing Science and Practice' a book considered in the industry to be the bible of brewing and I began my learning. Yesterday Jenny drove me to Fraserburgh where I stopped in the brewery and had a very nice chat with the head brewer Stewart Bowman and arranged all details for today's starting shift. My plan is to document this week in diary form for anyones interest and my own pleasure.

And so here I am, writing from Fraserburgh about to start my first shift at BrewDog in less than 2 hours. Less than a week after finishing my degree, and taking a job in a seemingly unrelated field I could not be happier