Crisp Malthouse Tour
Written by Mark || 05/19/17
Greetings from Scotland! While traveling in the old country, I figured I could not miss out on a tour of one of the UK maltsters that US home brewers have come to know and love. On Wednesday, I toured the Alloa maltings that is operated by Crisp Malting Group. Alloa is just one of Crisp’s five malthouses in the UK.
The Alloa maltings is one of the smaller modern day pneumatic malthouses, putting out about 28,000 tons of malt per year (for reference, Rahr Malting has the largest single-site facility, which does 460,000 tons per year). But it’s all relative – their batch size is still 90 tons, which could supply many a craft brewery here in the States.
However, their main market is not breweries – 10 – 15% of this year’s malt will go into local UK beers and the rest will become whisky. And most of that whisky will be grain whisky rather than single malt (for more info on whisky and its production, see our previous article). Alloa malt makes its way into Invergordon, a Highland whisky, as well as Chivas Regal, a global brand that everyone has seen in airport duty-free shops.
Alloa also supplies Daftmill Distillery, a craft distillery here in Scotland that is so new that they haven’t released a bottle yet. Daftmill has been a farm for centuries, but in 2005, the owners started distilling the barley they grow. Between the field and the still, the grain makes its way to Alloa to be malted.
Alloa Photo Tour
I had a phenomenal time touring the Alloa maltings, and the least I can do is share the experience with you through some pictures. The site manager Mike was a great tour guide, leading me through the entire malting process and sharing a good bit of the site’s history.
The Alloa maltings was originally built in 1896 as a floor malting operation. At that time, there were many breweries in Alloa that it supplied (the city had water similar to Burton-on-Trent, the British town that is often credited as the birthplace of the IPA). As you can see in the diagram above, the malthouse was stacked four malting floors high, with two kilns in the middle of the building, and grain and malt storage under the roof. The malthouse was converted to pneumatic malting with Saladin boxes in the mid 20th century, though much of the original building is intact.
Here you can see one of the old malting floors that still provides structure to the building. The maltsters of old would open and close those side windows to control the temperature inside the room, and of course turn the grain every couple of hours to keep it cool and untangled. The ceilings are only about 6 feet high, so the workers would develop ‘monkey shoulder’ from hunching over while raking and shoveling grain. I had to hunch over myself while walking through there to avoid bonking my head.
Now I’ll take you through the malting process chronologically, starting with the barley seed. These grain bins are used to dry and store the incoming barley from the August/September harvest. Farmers grow barley all along the eastern coast of Scotland, and much of the good farming land is concentrated around Alloa. Here they take in grain from farmers growing 50 tons up to 1500 tons, unlike the US where malthouses deal primarily with massive farms. Mike mentioned that grain quality has gotten much better since he started at a malthouse in 1994, in large part due to precision farming.
As you can see in this process flow diagram, the grain has a somewhat complicated path during the malting process. Much of the controls are automated, though there are still 12 workers at the Alloa plant monitoring and tweaking the process as needed. Workers are there from 6:00 AM until midnight in shifts of 7 people, and the malting goes on 365 days a year. A delay at any step of the process backs up the malting progress in every previous step, so delays cause quite a headache. Thankfully, they’re quite rare.
The grain is first steeped in one of four conical steep tanks. Then it is transferred across the malthouse to the second steep as a grain/water slurry, which flows much better than just grain. A new batch should go into the steep at 9:00 PM each night.
Mike is checking on the grain after the second steep, using traditional sensory methods to determine where it’s at. During steep, he would bite grain kernels to find out how much water they’d absorbed – the grain gets progressively softer during the steep.
Once it has finished steeping, the grain goes into a pregermination tank. This step is not done in all malthouses. The blades in the picture keep the grain mixed up.
Now grain is augured over to the germination room, where it falls through a ceiling into these Saladin boxes. These piles will be leveled and half of this grain will fall through the floor into another set of Saladin boxes below.
Here Mike is checking on the germinating grain to get a feel for where germination is at. In the background of this picture, you can see the rotating helical screws that move along the grain bed and turn the grain. This detangling mechanism was the greatest innovation of the Saladin box, allowing for a much deeper grain bed.
This grain had nearly finished germinating. At Alloa, they give their grain four days to germinate before sending it off to the kiln.
As I mentioned before, maltsters still rely on traditional sensory methods to check on the grain’s progress. Here Mike has ‘rubbed out’ the germinating grain to determine if modification is complete. If it is, the grain will spread into a chalky white paste as shown here – Mike has the experience to tell when the consistency is just right.
I only got a peek into the kiln room, as it was actively blowing hot air through the grain bed to dry it out. Mike had to brace himself against the door, as a powerful moist wind was forcing its way out of the kiln room when the door was unlatched. The grain will dry in there at relatively low temps for 21 hours, which preserves maximal enzymes for the whisky distilling. The kiln is the major bottleneck in the malting process, where most of the delays happen, and then it’s a game of catch-up for the next few days.
Finally, after the malt is dry and the brittle rootlets are removed, it will find its way into a storage bin for 4 weeks on average. Then it is dropped through these hoppers into trucks waiting below, to be whisked off to become delicious whisky. The malt might be distilled relatively soon, but the maturation will take a long, long time. The batches that were being malted during my tour might hit shelves in 2030, or much later. If this malt goes into a 43 year-old whisky, like the one I tasted from Invergordon a couple days ago, then no one will drink it until 2060. Whoa.
If you’re a home brewer or just a fan of brewery tours, then I highly recommend taking a tour of a malthouse. It’s an interesting process to behold, and in our experience, malting managers have been happy to show us around their malting facilities. Like brewers, they take pride in their product.
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