Does anyone have a recomendation for the minimum size a kettle drain should be for using whole hops? I want to use the existing drain - 2" and add a hop back prior to the wort cooler. Is the drain to small?
If you're stuck with 2" already, you can change your outlet valve to a full-port ball valve. Twice the opening of a butterfly. Optimum size will also depend on how the drain is located and how you can motivate it with your hose. A full two inch opening is small but could work with accurate motivation from the sprayer. You might still find it quicker to climb in and bucket it out. Sometimes I wish my 3" kettle outlet was bigger.
we have a 4" drain reduced to 1.5" butterfly valve by means of a 4" cap with a 1.5"TC welded on. Inside the kettle is a two part stainless strainer, think Phil's EZ masher from the old homebrewin' days. The wort comes out fast at first, then very slowly as the last bit drains. We let the grant fill as fast as gravity allows, then pump it clean. I still have to get in and clean it out by hand, pushing the hoppy mess out the hole, this is 7.5bbl kettle btw....