Mashing & Lautering
At the start of a brewday all the malt or grist is weighed out depending on the beer being brewed and added to the grist case (big hopper for holding the malt). The malt is then blended with hot liquor via the grist hydrator as it falls into the mash tun to get the desired temperature for the particular beer being brewed. Every mash at Cromarty is hand mixed in the mash tun to achieve a uniform consistency and temperature and is a single infusion mash. The mash is then left to sit for a period of time (about 1.5 hrs) to allow enzymes present in the malt to convert the exposed starch to fermentable sugars. The temperature of the mash is one of the critical factors determining which enzymes work best and thus what kind of fermentable sugar profile we will end up with. For example a refreshing pale ale would be mashed fairly low in our temperature range whereas a big dark stout would be mashed higher to give more un-fermentable sugars and thus more mouthfeel in the beer.
Prior to lautering the sugary liquid (known as wort) goes through a vorlof stage which basically means it is recirculated from the bottom and back in the top of the mash tun to achieve clarity. The wort is then drawn off via four exposed run off points into a central grant pumped into the brew kettle.