Why is flow so important?
It’s critical because without the right flow, you won’t meet your volume requirements. Imagine the panic of a waitstaff when their restaurant is full of patrons on a Saturday or Sunday morning, and their coffee urn or satellite brewer brews a little shy of half. You’ll get a nasty service call.
Although I probably should have said that the most significant reason why flow is significant is coffee taste. When in a panic mode, volume is all that matters to our customers. Once there, they’ll tell you the coffee tastes funny as well.
But let’s not overlook the obvious: something is wrong with our equipment, and you must fix it PRONTO!
You’ll most likely start with the obvious.
How to restore flow
Before it gets more complicated, let’s define our terms first. Flow, in this article, refers to how easily water flows through the spray head. That cleared (no pun intended), let’s begin.
The easiest and first place we go when restoring flow is the spray head. It’s easy to access. All you have to do is unscrew it. But what we see will show us the kind of repair at hand, whether a simple clogged spray head or a tank full of solids.
Some machine manufacturers have made this initial response easier. For example, Bunn has a tool that fits in the spray head tubing. Once removed, you can insert one of the ends into the tube and clear any buildup. The other end is used to clear the holes in the spray head itself. This is ok to do with metal spray heads.
Bunn Wilbur Curtis has switched to using plastic on spray heads. This is not just any type of plastic, but one designed to resist solids buildup. They are not perfect. Hey, nothing is.
Not all that shines is gold, either. Metal spray heads are not necessarily better. If you try to clean them, there’s a high likelihood that you’ll scratch them and build a bed on them for solids to build up. You can use a mild acid, like citric acid, to remove the buildup. Be aware that citric acid is more effective against scale from calcium, magnesium, or fluoride. Coffee grime is very tough to dilute. If you have some grime and scale buildup, sometimes it is better to replace it.
Might solve the problem or not
The bottom line is that cleaning the spray head is your first attempt at restoring flow. It may well be the final resolve to your problem. Remember to double-check water levels after restoring flow. You may need to recalibrate volumes or times.
Demystifying Coffee 