Most people are likely aware that oxygen can easily cause wort aeration during beer brewing. This can result in darker colored wort, a worse mouthfeel, and instability in the beer.
So, what causes wort aeration? Generally, there are three main reasons:
The mash flowing into the vessel on top of the tank.
A much faster stirring speed.
Transporting the mash via a pump.
And what should we do to avoid wort aeration? Please follow the methods below:
Install a malt hydrator.
Direct the mash into the vessel from the bottom of the tank.
Equip the grain rake or agitator with Variable Frequency Drive (VFD).
Current brewhouse units typically no longer use strong or powerful agitators. Instead, they use agitators that can modulate their rotating speed via VFD according to the capacity of the mash tun or cereal cooker. Additionally, when separating the mash during decoction mashing, the agitator should be stopped for about 5-10 minutes. This allows the undissolved malt to settle down to the bottom of the tank. After combining the mash, stir for 3 minutes.
Take care to avoid cavitation when transporting the mash.
Consider using inert gases like N2 during mashing.