Filtration is essential in the beer brewing process. The main filtration process is divided into 2 phases, first phase is after mashing and second phase is after fermentation. The article is focus on the wort and grains separating process.
The malt after mashing, it needs separate wort and grains. At this moment, the wort is hot (60-75 degree C), the membrane filter press is recommended to separate grains and wort, as it supports high pressure to squeeze grains cake and easily discharging. The process will be divided into 5 steps: Filtration, Pre-Squeeze, Grains Washing, Final Squeezing, Discharge.
Firstly, the wort will be feed in filter press from mashing tank. Firstly, the work will full in the filter press chamber, then the wort will pass through the filter cloth and flow into the outlet pipe, the grains will be intercepted by filter cloth and will fill full of the chamber. When the chamber is full of grains, the grains and wort are separated initially. This process usually takes 20-30 minutes.
In this stage, the feed pump has been turned off. The squeezing pump will turn on, and these membrane plates will be filled the pressured air or water, the membrane will expand to squeeze the grains cake.5~6 bar squeeze pressure is enough, because we don’t need to make the cake very dense at this stage.
The grains are still have valuable wort inside the cake, we need the hot water to wash the grains to collect more wort, the process known as “sparging”. Feeding clear water (70-80 degrees C) into filter press, it will flow through the cake of grains.
After sparging, the grains need to be dewatered as dry as possible. We shall turn on the squeeze pump again, to squeeze the cake by 15-16 bar pressure. It usually will take 10-15 minutes.
At this stage, the separating work is finished, press the discharge button, filter press will open the plate one by one, the cake will automatically drop down as the gravity. After cake discharge, you can wash the filter cloth and to prepare for the next cycle.
