Why does espresso split unevenly when using coffee machine spouts?

Uneven espresso splitting, where one spout flows more than the other or one side stays dry, has two main causes. First, the espresso machine is not level, so liquid favors the lower side; a spirit level and recalibration usually fix it. Second, channeling stops the coffee from converging at the center of the basket, so the two spouts receive unequal amounts.

Split spout handles remain common because combo packages make dividing a shot convenient. Modern split spout designs reduce deviation caused by channeling, but they cannot correct a tilted machine or a poorly prepared puck. Checking levelness first, then grind and distribution, covers most cases. The same attention to setup applies when using coffee machine equipment of any kind, including how to use a drip coffee machine at home.

When using a split spout handle to extract espresso, you may occasionally encounter inconsistent flow between the two sides, or even the extreme case of liquid flowing from one side while the other remains completely dry. Although this uneven splitting issue doesn't happen often, it's bound to come up after long-term use. Front Street will analyze the causes from two angles: first, the espresso machine not being level, causing liquid to favor one direction; second, channeling preventing the coffee liquid from converging at the center. We'll also explain the structural differences between bottomless handles and split spout handles, and why modern split spout handle designs can effectively reduce splitting deviation caused by channeling, helping everyone quickly identify and fix the problem when it arises.

Even now, split spout handles remain a key accessory for many shops, because coffee combo packages are becoming increasingly common, and split spout handles make it more convenient to divide the extracted espresso into two portions. However, uneven splitting does occasionally occur. To put it plainly, the amount of coffee liquid flowing from each side differs—one side gets more, the other less; in more severe cases, only one side dispenses while the other produces nothing at all.

Although this situation isn't particularly common, over time you'll inevitably run into it a few times. So today Front Street will discuss the reasons behind uneven splitting, so you know how to respond when it happens.

There are two main causes of uneven splitting, and the first may be simpler than you'd think—the espresso machine isn't level.

When the espresso machine is tilted, the evenness of the coffee liquid's split is affected. This is because liquid naturally favors the side that's easier to flow toward; if the machine tilts to the left, more coffee liquid will flow from the left spout, and vice versa. This situation is actually quite common—besides the machine never having been leveled in the first place, another possibility is that the tabletop has developed a depression after bearing weight over a long period, throwing off the machine's balance.

When this happens, the solution is simple, and I'm sure Front Street doesn't need to say much—just grab a spirit level and recalibrate the espresso machine's levelness.

The second cause is channeling. When extraction is normal, the coffee liquid, after being pushed out of the portafilter basket, converges toward the center, forming a single stream that drips downward, landing right into the central guide tube of the split spout handle, where it's evenly split. But once channeling occurs, the coffee liquid doesn't necessarily converge into a central stream—it may seep out concentrated at some channel location, and as a result, the split will naturally be uneven.

For this situation, Front Street has shared quite a few solutions before. Simply put, you need to distribute the grounds evenly and then tamp with even pressure. The root cause of channeling lies in uneven coffee grounds distribution or tamping pressure. When the density and amount of coffee vary throughout the puck, hot water finds channels that are easier to pass through.

Of course, besides that, static electricity causing coffee grounds to clump also creates density differences throughout the puck. So before tamping, it's best to break up the clumped coffee grounds first, then distribute and tamp, which effectively reduces channeling and makes the coffee liquid split more evenly.

In reality, though, the uneven splitting many friends encounter is mainly caused by leveling issues. This is because today's split spout handles typically have a small platform positioned before the split point; the coffee liquid drips down and first contacts this platform before being split. Because of this, the problem of uneven splitting caused by channeling has been effectively mitigated, which is why Front Street says that in most cases, it's still a leveling problem that's to blame.

- END -

The above content is compiled by CoffeeHunters, a coffee news website.