L is for Lautering
L is for Lautering – part 12 of our A to Z guide to craft beer terms.
Lautering, or separating malt sugars from grain, is one of the most important processes in brewing. It’s done in a lauter tun, which is a large vessel that holds the mash (grain and hot water mixture) and sports a false bottom to allow the wort to drain out and leave the grain behind. Broken down into three steps, lautering is a bit easier to get your head around, so let’s take a look at how we extract that sweet, sweet wort from a quite unwilling host.
Let’s back up a step. In order to make beer, we need to extract fermentable sugars from grain. This is done in a process called mashing in. Mashing is the brewer’s term for the hot water steeping process which hydrates the barley, activates malt enzymes, and converts the grain starches into fermentable sugars. Think of it as a grain soup. Lautering picks up after we’ve mashed in!
Before the brewer drains the sweet wort from the mash, many preform what’s called a mahout. This is done by raising the temperature of the mash to around 76.5 degrees Celsius in order to stop all that enzyme action and lock in the fermentable sugar profile. It also makes the wort more fluid, which means it can cruise down the grainbed and through the false bottom of the lauter tun. Take a deep breath – still with me?
Once that wort has worked its way through the grainbed, the first runnings are pumped back to the top of the lauter tun to be sent back through. As you can imagine, these runnings are quite cloudy, filled with proteins and little grain bits. We want a nice clear wort, and sending it back through the grainbed for a second time helps to filter out some of those undesirable materials. This process continues until the wort becomes clear. Then we’re ready for the next step.
There’s still a lot of sugary, fermentable goodness left hanging around in that grain bed. To get at them, we rinse that grain with hot water. This is called sparging. Water temperature is very important here, because if it’s too hot, mouth puckering tannins from the grain husks can be extracted, and nobody wants that! Water is added to the tune of roughly 1.5 times the amount as was used in the mash (remember that grain soup from the prologue). This process continues until the brewer has accumulated the correct amounts of wort.
Boom! You’re all done. Well . . . you’re about half way done with the brew, and our big system, you’ve still got at least four hours left!