Channeling vs Wrong Grind: Which First?

The core distinction

A wrong grind affects the whole bed consistently. If the grind is too coarse, water passes through the entire puck quickly. The puck is relatively even; it is just too permeable. Change the grind and the whole bed changes.

Channeling affects part of the bed. Most of the puck may be fine, but one path lets water through faster. The overall shot time may look normal or fast, but the extraction is uneven. Changing the grind changes the whole bed while the path remains.

So the question is: is the puck uniformly wrong, or locally wrong?

Test 1: Look at the puck after the shot

Knock out the puck and inspect it before it dries.

• Even colour, flat surface, no holes: points toward a grind issue if the shot was fast, or a correct puck if the shot was fine.
• Crater, hole, or pale patch: points toward channeling.
• One side darker: points toward an uneven bed or a tilted tamp.
• Puck stuck to the screen: points toward overfilling, which can cause channeling.
• Soupy, shallow puck: points toward underdosing or too coarse a grind.

The puck is not proof. A hole can be caused by knocking it out. But a consistent pattern across several shots is strong evidence.

Test 2: Watch the flow

• Even stream that starts and stays even, just fast: likely grind.
• Stream that starts dark, blondes early, then accelerates: likely channeling.
• Spurt or jet to one side: channeling.
• Flow that hesitates, then gushes: channeling or a seal issue.
• Uniform slow drip throughout: likely grind too fine.

Watch the first ten seconds especially. Channeling often announces itself early.

Test 3: Change grind and observe the response

This is the decisive test. Move the grind one step finer (or coarser) and keep everything else the same.

• If the shot improves in a predictable, proportional way: the grind was the main issue.
• If the shot stays uneven, spurts, or gets harsher while slowing: channeling is likely.
• If the shot swings unpredictably: prep consistency or the grinder is the issue.

A grind change that makes the shot slower but no more even is a sign that you are compressing a channel rather than fixing the bed.

Which first?

For most home setups, check in this order:

1. Basket fit and dose. An overfilled or underfilled basket creates unevenness that looks like channeling. This is quick to check.
2. Distribution and tamp. Level bed, square tamp. If these are visibly wrong, fix them before grinding.
3. Grind. If the puck is even and the prep is sound, adjust grind.
4. Machine. Last.

In other words: rule out channeling causes first when the evidence points to unevenness, but do not rebuild your whole routine before a simple grind test. The practical rule is:

• Even puck + fast/slow shot → grind first.
• Uneven puck or visible spurting → channeling first.
• Unsure → do one grind step and watch whether evenness changes.

Why grinding finer can worsen channeling

A finer grind increases resistance everywhere. If a channel already exists, the pump pushes harder, and the channel can become more pronounced. The shot may slow overall while the channel extracts even more. The result is a cup that is both bitter and sharp, and a puck that looks worse.

This is why "grind finer" is bad advice when the real problem is a crack, a gap at the basket wall, or a dense clump.

A diagnostic table

What to log

Record the evidence, not just the verdict:

The middle row is the key: once the puck is even, a grind change becomes interpretable.

Bottom line

A wrong grind changes the whole bed; channeling changes part of it. Inspect the puck, watch the flow, and make one grind step as a test. If evenness improves, it was grind. If it stays uneven or gets harsher, fix prep and basket fit first.