How to Brew Gluten-Free Beer: Lautering

This is the next post in our series in How to Brew Gluten-free Beer. In our last post, we covered the mashing process. Now we move on to the next critical step: Lautering.

Just before this, the grains were mashed, or heated in water, which extracted the starches and converted them to sugars. But this left us with a soupy mixture of “spent” grains, water, and sugar. The grains must be removed to continue with the brewing process.

This is accomplished by lautering, which takes place in a Lauter Tun. This tank looks very similar to (and is sometimes the same thing as) a mash tun, though inside the tank is a false bottom with slits in it. This false bottom allows the the liquids (called the wort) to pass through while holding back the solid particles. The Lautering process consists of three stages.

  1. Mashout: Technically the last stage in mashing, this preps the mash for lautering. The mixture is is heated to make it less viscous (thick) and easier to separate.
  2. Recirculation: The wort is circulated from bottom of the tank back to the top to begin the filtration process. This step is necessary because while the slits at the bottom can hold back the larger particulates, they cannot block the smaller granules and debris. However, as the wort is pulled from the bottom of the tank, the larger grains are pulled to the bottom, forming a sand filter that blocks the smaller particles and filters the wort. But this means that the first wort that is pulled will not be completely clear, hence the need for recirculation. This is also known as vorlauf, which is a German word for temporary.
  3. Sparging: Water is trickled through the mash to increase sugar extraction. This allows the brewer to extract as much sugar as possible from the grains. This water can be circulated through the grains in several different ways, such as continuous sparging where the water is added after most of the wort is drained at a rate equal to the drain rate, keeping the water level constant. Sparging must be done carefully so as not to extract tannins, which will make the beer bitter.

At the end of the lautering process, the wort has been removed from the grains, which can now be disposed of. This is a similar process regardless of whether you are using regular or alternative, gluten-free grains. However, if you do not start with grains and instead start with an extract (a syrup created by boiling the wort) then it is not necessary to mash or lauter. Regardless, at the end of this process, you have a sugar-rich liquid that’s ready for the next step: boiling.

We’ll dive into this topic in a few weeks. In the meantime, go try to brew some gluten-free beer! If you need help and suggestions, we’d love to talk to you. Post a comment or send us an email at aurochs[at]