Every brewer knows that making good beer requires starting with a good wort, but many new brewers get confused on the best ways to get a good wort. Many new brewers focus exclusively on things like the grain-bill or malting and milling techniques, ignoring the significance and impact that the water. Effective controlling the water is absolutely vital to getting the most out of the grain, and the easiest way to quickly boost the water effectiveness of any mash / lauter system is to use a false bottom.
A false bottom in the mash tun holds the grain above the real bottom while still allowing water to pass through. This dramatically improves the ability of the water to circulate evenly through the grain. An increase in circulation translates into a rise in the overall amount of sugar that can be coaxed from the grain, and a more complete, better tasting beer.
The reason for this improvement is two-fold. The first reason is temperature control. If the mash is too cold, sugar will not be efficiently released from the grain. This can lead to a low alcohol content and watery tasting beer. However, if the temperature is too high excessive tannins and other off-flavors can be released, potentially ruining an otherwise awesome brew. It is much easier to control and adjust the temperature of a mash if the water is flowing easily. This control is helpful in any brew, but is 100% necessary for advanced brewing techniques like multi-rest mashing.
The second reason is that flowing water helps rinse the sugar from the grain. Everything else can be perfect about a mash, but if water is unable to rinse the sugar away from the grain the wort could be left as little more than dark and slightly-sticky grain juice. Without a false bottom, the grain bed sits on the bottom of the kettle. This solid mass doesn’t leave any room for the water to flow. This causes the water to create channels to stream through, and can eventually clog altogether. A false bottom helps to alleviate this by elevating the entirety of the grain off the kettle floor, leaving plenty of room for water to move freely.
There are alternatives to a false bottom, such as a kettle screen or a brew sock, that can produce similar results. However, each of these alternatives comes with a slew of drawbacks. A brew sock, for example, is a common early starting point for homebrewers. It keeps all of the grain contained and easily and allows for an easy transition from extract brewing to partial- or full-mash brews. The containment also comes with the cost of restricting water flow to the grain near the core of the ball. Similarly, a kettle screen causes certain parts of the grain to be missed. Though, with a screen this is caused by the water channeling through a limited number of paths of least resistance. Channeling while using a kettle screen can be avoided by batch sparging, but a constant sparge keeps the sugar from resettling in the grain.
All of this boils down a false bottom leading to a dramatic increase in efficiency for the brew. This can really be a game changer for new brewers learning to get the most out of the brewing experience. Not only does it allow the brewer to get higher alcohol content beer using less grain, but it also provides the brewer with greater control of the final product and greater access to advanced techniques. To get really great tasting beer, beer that perfectly matches the imagination of the brewer, the mash / lauter tun should utilize a false bottom.