The Wonderful World of Malt
Date: 17 May 2017
I hopped in the van for a trip to Cork on Monday. MCI or Malting Company of Ireland was the destination. These are the guys who take our Kilkenny grown Barley and malt it so we can use it for brewing.
For those of you in the know about Barley we use the variety Propino. As you may also know only the finest grade barley is malted for use in brewing.
We have done extensive taste and brewing tests with every malt available to us and settled on MCI Ale Malt for use in our beers. Not because it’s Kilkenny barley, but because it’s the best barley. Take a bow Kilkenny Barley growers, you’re the finest in the country.
I met with Chris in MCI and he gave me the guided your. I’ve been to quite a few maltings over the past decade and know the process quite well. What MCI are doing is impressive. They screen the barley to extract the unusable grains a number of times and you can see the quality in the end product.
Malting is a multi stage process and each stage is a control of temperature and moisture levels to facilitate the barley to first reach the desired moisture level (steeping), then germinate, then dry and finally storage.
There is a reason most maltings are in existence for decades, the scale and complexity of the equipment is vast but more importantly the skills and craft of malting is something perfected over years and then passed onto the next generation.
MCI malt in batches of 160 tons split across 3 steeping vessels. Each vessel is designed to control aeration of the bath of barley to allow the barley to absorb moisture until it reaches the desired level. At MCI they do this in a 3 stage steeping process of Wet – Dry – Wet – Dry – Wet – Dry.
The idea of the 3 stages is to treat the barley very gently and allow it to breath in between wet periods, in effect to stop the barley from drowning.
The barley is then transferred to the germination vessel. In here the seed is rotated every 10 hours to trick the seed into not sprouting. They don’t know which way is up as they are flipped on their head every 10 hours.
The coils / screws you see here are what are used to do that flipping. The seed germinates over the course of 3 days. Again moisture and temperature levels are tightly controlled with the use of heated air blown up through the floor. During germination the seed releases enzymes that start to convert the starch to sugars. This is the crucial part for us as brewers, these sugars are what we brewers call “fermentables” and our yeasty friends love them.
Once the barley seed has adequately germinated and the desired level of starch conversion has taken place the barley is then transferred to the drying vessel.
In this vessel heated air is forced up through the grain bed to allow the seeds to dry out. The key element to control at this stage is the variance between temperatures at the bottom of the grain bed and at the top. We want malt dried evenly. When you walk into this room you are hit with a blast of warm moist air a bit like getting off an aeroplane in some exotic country with a mix of monsoon and heat wave weather combined.
Finally the barley is passed through a final screening process and prepared for storage. Malted grain can be stored for a number of months before we use it for brewing. Again temperature and moisture levels are tightly controlled during storage.
The final step in preparing the grain for brewing is to crush the grain. This is to breach the hard husk of the barley and allow the sugars out. Take a look at the grain mill. The crucial part to control here is the crush, we want a nice mix of fine crush (flour) and husk. The correct crush is vital for a successful mash.
Finally we have the crushed barley all bagged up and ready to take to the brewery.
So when you’re out enjoying a Pint of Costellos remember the input of the Kilkenny Barley growers and our maltsters. Enjoy.