Why is it leaking from the joint when I'm brewing?

It sounds as though you are not getting a tight seal on the cylinder(s). This may be caused by not locking the joint in tightly. Please be sure that you pull the joint lever firmly and hear a "click" to lock the joint in place and provide a tight seal prior to brewing. This should solve the brewing and leaking issues. There is also an available video for best practices for using the Siphonysta. If you need any further assistance, please reach out to our support team.