Diary of a Brewer: Malting

With my graduation occurring in the past week and a half I have had little time to keep up with my documentation of brewing techniques and general brewing information. Now that things have calmed down I have found more time to devote to the study of brewing and the pursuit of a brewing career. I know malts must seem like a dull subject to the non-brewer but they are possibly the single most important ingredient in any beer and so should not be overlooked. Here I wish to examine the different types of malt, their flavour characteristics, their creation and wide range of uses.

The malt that we use in brewing is a derivative of cereals (themselves a type of grass). The grains of the cereal are the seeds they produce and come in a variety of forms. These grains consist of several components, most simply the endosperm, germ and bran. The bran is the outermost casing of the grains and contains most of the fibre found in the grain. The germ is the embryo of the grain that will facilitate the reproduction of the plant and as such has a very high protein content. And the endosperm is the soft tissue inside of the grain, rich in carbohydrates and starches, that will provide the nutrients for the germ. It is this starch rich component of the grain that is of most use in the brewing process. 


The process of extracting fermentable sugars from the raw cereal grains begins by harvesting fresh grains and drying them to a moisture content of around 12-15%. These semi-dried grains are then rested for several weeks. This step is undertaken because fresh grains have an intrinsic property known as seed dormancy whereby variations in the characteristics of the grains ensure a natural defence against mass simultaneous germination. Once the grains are held at this dormant stage for approximately 6 weeks they are steeped in water ranging in temperatures from 12-18C depending on the dormancy of the grain. During this steeping process the grain swells to ~1.3 times its original volume at which point the grains need to be agitated by blowing air into the steeping vessel to prevent them from becoming too compacted. This process provides the microbes on the surface of the grain with oxygen and allows them to begin degrading the surface layers of the grain. As this process continues the steep water becomes more and more riddled with microbial metabolites and so is often changed several times during the steeping process. After the steeping is complete the grains are dried by sucking humid air downwards through the grains to eliminate any residual moisture or carbon dioxide. Often at this stage the grains have started to germinate. 


At this stage the grains are transferred to either a germination vessel of a floor malting room where they will continue the process of germination under strictly controlled conditions, often kept at a very precise humidity and turned regularly to prevent the grains from growing together in masses. The indicator of germination is the 'chit'; a sheath that grows from the base of a germinated grain. The grains are held in the germination stage until the acrospire (a protein growth under the husk of the grain) has reached ~75% of the length of the grain. If germination where allowed to progress until the acrospire were longer it would not result in higher extract yields and thus would be inefficient. 

After the germination is deemed complete the malt is ready to be dried, or kilned, to produce the correct colour and flavour profile desired. Kilning consists of layering the grains about a metre deep and blowing warm air through the grains from beneath. Because the grains are still moist the warm air will dry the lowest layers of the grain before cooling and becoming saturated with moisture. Therefore the grains closer towards the surface are still warm and damp and can continue to germinate. The boundary between the dry grains and the damp grains above is called the dry-zone and this dry-zone will move upwards through the grains as time progresses. At a certain point the dry-zone will reach the surface of the grain bed and the break-point occurs. At this point the airflow through the grain is decreased and the temperature is increased. Once the grains have been kilned to ~80-105C the production of pale malt is basically complete.


Some of the pale malt will be diverted and used in the production of speciality malts (although green malts and kilned malts are sometimes used). Malt is loaded into a rotating cylinder that can be heated either directly or indirectly to roast the contents. During this roasting stage the colour of the malt will darken and enzyme destruction will occur. The temperature, type of input grains and duration of the roasting are varied depending on the desired colour and flavour of the final malt. Finally the malt is cleaned, milled and packaged ready for use in mashing. 

Diary of a Brewer: The Search Continues

So a few days ago I received an email that seemingly changed everything. After working a trial week at BrewDog, and possibly being a bit too confident about my chances of getting the job, I received an email informing me that I had been unsuccessful in gaining the position of Assistant Brewer. Needless to say this put a damper on my attitude towards my future brewing prospects. So after a few hours of some self-indulgent loathing I realised that I needed to make the best of the situation and I started applying to every brewery I could find. Along the way I have had several people ask me why a recent St. Andrews graduate was applying for minimum wage positions in which I will likely do nothing but clean for the first few weeks, that is IF I get the job. And up until yesterday I didn't really have an answer to that question. I simply responded with "I don't know, I just want to be a brewer".

It was yesterday afternoon that I was watching a video of Stephen Fry speaking at the Sydney Opera House sometime in January 2011. For those of you who don't know (and I find it hard to believe many people fall into this category) Stephen Fry is a British national treasure and a brilliantly intellectual man. He gave a 45 minute talk at the Sydney Opera House about nothing and everything at the same time, and I have never been so captivated by a monologue. During his talk he mentions a scene from a film called 'The Red Shoes'

"It's one of the great films; he's one of the great directors Michael Powell. And there is a scene in it that means a great deal to me; it's quite corny in a way but it's so perfectly done because it's Michael Powell and written by Emeric of course. Moira Shearer plays this young girl who is a ballet dancer and there is this entrepreneur, an impresario I should say, played by the fabulous actor Anton Walbrook. And her mother takes her to the opera house. So she goes to see this ballet, and in the interval there is this impresario played by Anton Walbrook, and her mother drags her up to him, taps him on the shoulder, and he turns round rather wearily. And she says "I want to introduce my daughter who is a magnificent young ballet dancer, and she should join your company, she wants to join your company". And he raises his languid eyes and looks at her and says "why do you want to join my company". And the daughter says "well I've heard it's really very good, it's the best I think, you're positivity wonderful and I like dancing and I think it would be wonderful fun!". And he just simply turns his back on her and walks away. And the mother goes "well!" and drags her daughter back saying "what a rude man!". But you could see, she stands there the daughter, absolutely fixed. The camera moves in on her face, her eyes are sparkling with.... you can't tell what is it.... furry because he's been rude? It's something, something very big to her. And she goes up to him and she taps him on the shoulder this time; not her mother. And he turns round and looks really annoyed..... "What?”. And she says "I just wanted to tell you I was wrong about what I told you when I said I want to join your company because it's a good company and I like to dance. It's not that I like to dance, I HAVE to dance. It's what I was put on the planet to do, it's what I am here to do, I have to dance.", And he stares at her, "Come round in the morning" he says. And then her career begins. And it’s a wonderful moment because you do realise that for some people, lucky people, there is this imperative, this absolute need to do something, you just know it's what you have to do. And it almost doesn't matter whether anyone is going to pay you or not to do it, you have to do it."

And it was at this point that I had my reason. I don't know why, and perhaps I will never know, but at the moment I feel that working in the brewing industry is something I have to do. I would certainly do it whether I was paid or not. And that, I feel, is an attitude towards a line of work that is invaluable. How many people do you know who would show up at work if the boss said they couldn't pay them? 

This career is something I truly enjoy..... now I just need to find someone who will let me do it. 

Diary of a Brewer: St Andrews Brewing Company

So after returning to St. Andrews from Fraserburgh I've wasted no time continuing my affinity with breweries. On this occasion I volunteered with Bob Phaff, the owner and founder of the St Andrews Brewing Company. Bob founded this microbrewery in January of this year and has seen great success thus far, receiving a warm welcome from more than 50 local restaurants and farm shops. In May I spent a few days helping Bob at his brewery and returned from Fraserburgh just in time to be of assistance again yesterday.

Bob has been active in the beer industry for quite a while, working at breweries and even writing a book about the microbrewery scene in Idaho where he lived for a few years. when he first came to St. Andrews he asked if he could try the local beer and was shocked to find out that there wasn't one. Obviously a gap in the market that needed to be filled, and who better suited than a microbrewery enthusiast to fill it. So in January of 2012 Bob saw the arrival of his brewing kit, comprising of a 10 hectolitre (hl) hot liquor tank, a ~3 hl mash tun and a ~7 hl copper and he has been producing great beers ever since.


Bob gave me a lift from St. Andrews to Glenrothes yesterday morning at 7:00am to start a day of bottling and labelling. Bob runs a one-man operation and so is extremely busy and always open to having some extra hands volunteering. Our first task was to put labels on a batch of Nuek Ale that had been maturing for the past few weeks and was now ready to be labelled and boxed up for sale. This involved stamping the best before date as required by law on the labels before applying them to the bottles. Then we applied the labels by hand to all 150 bottles. This proved to be a labour intensive and time consuming process. We also ended up putting labels on about 120 bottles of Fife Gold and 240 bottles of Oatmeal Stout, by the end of which I wished I never had to see another bottle label for the rest of my life.

In between the labelling of the three different types of beer we bottled a batch of 70/- that had been fermenting for the past 7 days or so. The volume of the fermenting vessel was about 400 litres, so accounting for waste and sediment we were aiming to bottle about 750 beers. The first step was to gather several rows of clean bottles straight from the pallet they arrived on. We lined these bottles up on the bench next to the fermenter and using a funnel filled each one with a small amount of sugar to facilitate fermentation in the bottle to produce carbonation. This step must be performed because the fermenting vessel that Bob owns lacks the ability to withstand pressures up to  3 bar necessary for CO2 to be present in the beer prior to bottling.

Two by two, and by hand, the bottles are then fitted onto the arms you can see protruding from the mechanism we use to fill the bottles. This machine automatically siphons beer from the tank into the bottles filling them to exactly 500ml; once filled we simply have to unclip them and line them up to be capped. This capping process was done in about 50 bottle batches repeated until we had bottled nearly 700 beers. These beers were then moved onto pallets for them to age. Because of the set-up that Bob has (mostly his limited storage capacity) the bottles sit unlabelled until they are ready to sell. This is because every time that Bob boils a batch of beer in the copper the entire room steams up and this would strip the labels off of the beer bottles.

After cleaning all of the supplies that we used to bottle including the brew tank that we emptied we then moved all of the labelled bottles to the small storage area, gave the floor a quick mop and prepared the ingredients for the next days brew. Bob was going to be brewing a batch of 80/- for the first time and wanted to make sure that all his supplies were ready to go for a 7:00 start the next morning.

I'll be working several days with Bob over the next few weeks (when I find free time amidst graduation and career searching). I've thoroughly enjoyed my time working him thus far and am looking forward to learning much more from the one man team that is the St Andrews Brewing Company.

Diary of a Brewer: Mashing Methods

Now that my trial week at BrewDog is over I have returned to Saint Andrews to await word from Nikola (the brewery manager) as to whether or not I will be offered the job. In the meantime I have decided to start learning the science of brewing with the same devotion I gave my university degree. I have been taking notes from Brewing Science and Practice, a book you will note I have mentioned several times thus far in my writing. I figured the best way for me to learn from this book, considering that I have no course outline as when at university, is to document the notes that I take and transcribe them into blog posts for anyone’s interest.

So I’ll begin with a short entry detailing the different types of mashing methods used in brewing.

Mashing is the process of extracting fermentable sugars from malted grains to be converted by carbohydrate metabolism into ethyl alcohol (ethanol), carbon dioxide and heat. The enzymes that degrade the starches into fermentable sugars are effective over a wide range of temperatures, although different temperatures have different relationships between extract yield and incubation time. To maximise the extract yield while minimising the incubation time several different methods of extraction are used. Among these methods are isothermal infusion mashing, decoction mashing, double mashing and temperature-programmed infusion mashing.

1.       Isothermal Infusion Mashing –

This is the mashing method currently used by BrewDog. Coarsely ground malts are mixed with liquor      (63-67C) at a precisely controlled rate and temperature producing a thick porridge-like mash. This mash is then rested at this temperature for 30 minutes to 2 hours. The initial run-off from the mash tun is cloudy and so is re-circulated into the mash tun allowing the bed of coarse grains to filter it clear. Sparge liquor at approx. 80C is then washed through the malt during collection of the wort.

2.       Decoction Mashing –

The malts used in decoction mashing are very finely ground and are mixed with mash liquor at a relatively low temperature to create a very ‘thin’ cool mash. A portion of the mash (usually 1/3) is then removed and boiled before being returned to the original mash, thus raising its temperature. After a rest of about 30 minutes the process is repeated and the temperature is raised again. Depending on the portion of the mash that is withdrawn for boiling the process can be done in either two or three steps, known as double and triple decoction mashing. These rests at certain temperatures allow the enzymes present in the wort to degrade different types of fermentable sugars. This type of mashing, because of the finely ground nature of the malt, requires the use of a lauter tun or mash filter to remove the spent grains from the wort. This process gathers about 2% more extract from the grains than infusion mashing, and was likely employed as a mash method when stringent temperature regulation of the mash was not technically possible.

3.       Double Mashing –

This is a method favoured when there are large amounts of adjuncts (non-malt sources of extract) to be added to the mash as well as nitrogen-rich malts. The basic principal is that two mashes are prepared, one comprised of the adjuncts (as well as 5-10% of the malts) that is heated through a range of temperatures before being boiled and liquefied, while the malt is mashed at a relatively low temperature (35C) favoured by the high nitrogen content malts. After a rest period of an hour the two mashes are combined raising the temperature to about 68C. This temperature is maintained for 15-30 minutes before being raised via steam injection to 73C. Finally the finished wort is lautered to remove the small grains present due to the liquefaction of the adjunct mash.

4.       Temperature-Programmed Infusion Mashing -- 

This method of mashing is essentially a combination of isothermal infusion mashing and decoction mashing. The mash is prepared with finely ground malts (making lautering a necessary process) and is heated through a range of temperature steps similar to decoction mashing but performed by steam injection or direct heating as opposed to boiling portions of the mash. This method allows for the tightest regulation of temperatures and rest times and is favoured by many large breweries.

Obviously the range of techniques described here can all be investigated in enormous detail. I will most likely be describing these methods further in a subsequent post but for now I simply wished to make myself, and others, aware of the different methods breweries use in the production of wort through the mashing process.

Diary of a Brewer: Trial Week Part 3

Link to Diary of a Brewer: Trail Week Part 2

I worked my final shift during my trial week at BrewDog last night, again working the night shift from 22:00 last night until 6:00 this morning. A very quiet shift in comparison to the others over the past week. I arrived to find that the afternoon shift had already mashed in on another batch of Paradox, transferred it to the copper and had already cleaned the mash tun (to my, and my body's, great delight).

Before we could begin the boil on this batch we had to make sure the original gravity was up at 1112.0, a formidable task considering the wort was resting at 1090 after the transfer. This rise in gravity is achieved by the addition of malt extract. Malt extract is used instead of malt because the weight of malt required to attain a gravity of 1112 would mean mashing with a liquor to malt ratio of ~1ml/g, far too close to the lower threshold where successful sugar extraction is not possible from the malt (see figure 4.14 contained in section 4.3.7 Mash thickness, extract yield and wort quality in 'Brewing Science and Practice'). The malt extract that we use comes in 25kg drums and is rated as 80% solids. These drums must be mixed with some of the heated wort in order to become viscous enough to be effectively mixed in with the contents of the copper. This process takes about 45 minutes per drum of extract, and after each drum is emptied a gravity reading must be taken to gauge if further extract is needed. Oscar added 225kg of extract to the wort last night, taking about 6 hours in total. During the time that Oscar was adding extract I was off performing the tank actions for the day and doing more PG checks to monitor the progress of tanks with active fermentation. About 2:00 in the morning when I had finished these tasks and Oscar was occupied with extract addition Stewart asked me to set up a tasting panel.

Tasting panels are routine tastings of the beer in the fermenters at various stages in their production. These stages include Fermentation, Cooling, Dry Hopping, Ageing and Filtration. Beer production is a very scientific process but sometimes it can only be classed as an art. These tasting panels are used to judge, based mostly on taste, if a beer is ready to be moved onto the next stage of production.

Stewart gave me a list of 9 FV that I was to collect samples from and label glasses with the FV number for tasting. This was an easy task until I tried to gather a sample from FV16 containing a 14% triple dry-hopped IPA named 'Anarchist Alchemist'. Because of the massive amount of hops added to this FV for dry hopping (something in the region of 400kg for a 100hl tank) the hops had blocked the port that I was using to collect a sample. Stewart helped me, very 'scientificly', remove the cover to the port and unblock the hops with a sanitised screwdriver. Keep in mind that located above the 1/4" port is 10,000 litres of liquid, weighing in at a very conveniently calculable 10 tons. When the port became unblocked a jet of hops and beer under enormous pressure came shooting out of the port covering both of us and nearly knocking the bucket out of my hands that I was using to frivolously manage the mess. We had our sample though!

The tasting panel was one of the most interesting things I have done during my trial week. Clearly being able to taste the subtle differences in these beers at various stages in production is a skill acquired over a long period of time. I suggested to Stewart that my ignorant input would likely be of no value to the company and so I simply tasted and discussed the beers with Stewart and Oscar rather than write my evaluation to be handed into the lab. As someone who had not tasted many beers that had just been dry-hopped, or had yeast contents that were off the charts, I was amazed that they were able to drawn any conclusions based on samples that tasted like dough or drain contents to the untrained pallet. Anarchist Alchemist tasted like you were eating a handful of hops (an experience only tangible if you have ever done so) due to the recent dry hopping, while the complexity of 'Paradox Isle of Arran' was amazing. A very humbling and gratifying experience.

And so in the early hours of the morning -- with brilliant sunshine basking all of Fraserburgh -- I finished my time at BrewDog, at least for now. I'll be in correspondence with Nikola to find out if I have the job and when I would start. I emailed James Watt and Stewart inviting both of them to the BrewDog tasting I mentioned in '24 Bottles of Beer on the Wall' before headed in the bed this morning. So here I sit, back at the Elizabethan Pub in Fraserburgh to pen the last of my 'Trial Week' entries in my journalling of my time at BrewDog. Jenny is driving up from St. Andrews as I write to spend the night and drive me home tomorrow morning.

My best estimate is that I lifted in the region of 10,000 kg of malt this week and aided in the production of approximately 45,000 bottles of beer. It has been an amazing, informative and tiring week. And I can only reflect on my time in Fraserburgh with the fondest of memories and the highest of expectations for the months (and possibly years) to come.

Diary of a Brewer: Trial Week Part 2

Link to Diary of a Brewer: Trial Week Part 1

So the shift rota over the last few days has allowed me to catch up on some sleep and has even been sparse enough to allow me to write another entry! I wrote 'Trial Week part 1' while sitting in The Elizabethan pub after working the morning shift on Wednesday knowing that I did not have to be at work until 22:00 on Thursday night. Naturally I was exhausted and should have finished my writing and gone to bed. But this would have been the sensible, and far less fun thing to do.

The bartender, a very nice man named Raymond, brought me a free pint of Punk IPA as a 'welcome to Fraserburgh and welcome to BrewDog' just as I was finishing the last paragraph of my previous entry. And after I finished writing I joined him and few of the locals at the bar to enjoy said pint. They were a great group of people who were very welcoming and enthusiastic about my new job prospect, so much so that I didn't pay for another drink. When 1:00 in the morning came round, and we were filing out the door of the pub, Raymond asked me if I wanted another drink. Apparently we had all gotten up, and made it out the door of the pub, because this was the only way to convince one of the locals (who was quite drunk) that it was time to leave. Once he was out of sight we all piled back into the pub and resumed our places at the bar. Raymond had given me the wireless code for the bar earlier in the evening so I pulled my laptop out and put on a selection of songs that those sitting at the bar requested. The drinks kept flowing and before we knew it we were all stumbling out of the bar at 4:30 in the morning. A fine welcome to Fraserburgh!

Needless to say, because of my antics the night before (including god knows how many pints of Punk IPA) I slept for the majority of Thursday before starting the night shift at 22:00. I was working with Oscar, one of the assistant brewers, and Stewart. When we arrived the afternoon shift had just mashed in on a batch of Paradox. Paradox is a 15% imperial stout that is aged in Scottish Islay whiskey casks. Because of the high alcohol content of this beer compared to standard ABV beers it requires 1350kg of malt to produce 30hl of wort with an original gravity of 1090. This however is not high enough and so requires the addition of ~150kg of malt extract to raise the gravity to 1112.

Because of the high grain bill and relatively low yield of the wort the mash is done with a liquor to malt ratio bordering on 2ml/g. When the ratio gets this low care must be taken to sparge and transfer the wort VERY slowly into the copper to ensure the very high original gravity target. As mentioned previously we normally transfer from the mash tun to the copper in 3 hours. This particular batch of paradox took nearly 5 hours to transfer. While the transferring was happening I was busy with another round of tank actions as well as PG checks, or as they are less affectionately known 'waste of beer checks'. These checks involve drawing 2 litre sample of beer from any FV filled with actively fermenting beer. The sample must then be de-gassed by pouring it back and forth between two vessels for several minutes. The programmed temperature of the FV is noted as well as its actual temperature. We then take a hydrometer reading of the de-gassed beer and manually take its temperature to adjust the reading according to a table of temperature and gravity specific adjustments. These values are documented at 3 hour intervals for the duration of the fermentation. This way any anomalies (in gravity or temp.) can be found quickly, and any stuck fermentations can be discovered before they cause too many problems.

I feel I should speak more about why the transfer of the paradox mash took so long and how we know we need to run a transfer this slowly. When we move the wort it flows out a pipe connected to the bottom of the mash tun located at the centre of the false bottom. This pipe then feeds into the bottom of a 35 litre pail (underback) that sits between the tun and the copper; another pipe feeds out the other side of the bottom of this underback and is connected to a pump that will move the wort into the copper. The first step in transferring the wort is to close the valve that leads to the pump while opening the valve that drains the copper so that the underback begins to fill. Depending on the size of the desired batch we are aiming for the underback to fill with 35 litre of wort in 100-120 seconds. When we have adjusted the valve on the bottom of the mash tun so the underback is filling in this specified time we know the hourly flow rate out of the mash tun. We must then open the valve leading to the pump so that we balance the incoming and outgoing flows from the underback. Every 45 minutes during the transfer we must document the flow rate, the gravity reading and pH of the wort in the underback, and the volume of the copper thus far. We should see a steady rise in successive values of gravity followed by a steady decline. Gravities that are too low tell us we should slow the transfer, and gravities that are too high mean we should increase it by adjusting the flow rate from the mash tun into the underback. Hence the Paradox took nearly 5 hours because our gravity readings from the underback were consistently below our target and the flow rate was reduced several times in an effort to raise the gravity.

After the transfer was complete I shovelled out the mash tun for the third time this week (an also found out from Stewart that the temp. in the mash tun is regularly 80C+). Once the grains were shovelled out I housed down the inside of the tun and prepared it for the next batch of malt. Surprisingly when I had finished cleaning the tun the shift was over. It was already 6:00 in the morning and the first shift was arriving. It was a very busy and informative night but we had only managed to complete the mash and transfer, and we were just beginning the boil after 8 hours of work.

I suppose there is a reason that Paradox costs £6.50 a bottle.

Link to Diary of a Brewer: Trial Week Part 3