How much malt can I use in the Brew Monk? Maximum 8 kg in the Brew Monk B40; 12 kg in the Brew Monk B50; 18 kg in the Brew Monk B70. Related articles What is the minimum batch size in litre for a Brew Monk? Up to what temperature can I use the pump? The bottom of my Brew Monk is burned. My Brew Monk switches off while I'm brewing. My Brew Monk does not reach its boiling temperature.