Serving People Serving Coffee Since 2005
Issue link: http://baristamagazine.epubxp.com/i/804825
110 barista magazine something is not right with your grinder. It could be that your burrs are dull (this is a common cause of most of the problems in your grinder, if you haven't noticed!) or that when they were in- stalled, they weren't balanced properly. If that's the case, you—or better yet, your friendly neighborhood service technician—may need to disassemble, clean, and reseat the burrs. If they're not perfectly parallel with each other, you'll defi nitely get a noticeably inconsistent grind. —Alex How can I control water fl ow of the espresso machine? How can we measure? Since Alex took two grinder questions, I'll take another fl ow rate question! I'm sure some of you have noticed that the brew pressure gauge on your espresso machine might move around a little bit when you're not pulling a shot. That's because it's reading the downstream line pressure before the pump is engaged. It's a great idea to make that pressure as consistent as possible to help prevent fl ow rate issues, and it'll give you a more consistent pre-infusion across the group heads. I like to install small accu- mulator tanks that have a pressurized bladder, and sometimes a pressure regulator with a gauge to help hold the line pressure around 3 or 4 bar of pressure (44 to 58 psi). The accumulator helps with keeping things like water hammer at bay, and the regulator keeps the pressure where you want it. When adding these types of items, it's important to remember that pressure and fl ow rate are not the same thing. Pressure regulators can often reduce fl ow rate, so if you add one, you'll want to make sure that your fl ow rate meets your equipment's requirements. You can test the fl ow rate by disconnecting the machine's supply line and observing how long it takes to hit the gallon mark on a graduated cylinder. If it takes 30 seconds, your fl ow rate is 2 gallons per minute (GPM). The only way to measure pressure is by installing a gauge somewhere in line with everything. It can get tricky balancing pressure and fl ow rate, which is why I would recommend having your coffee tech help out with this one. —Double J