How to brew better coffee

A long page, so scroll depth has something to measure.

Scroll slowly and watch scroll_depth fire once at 25, 50, 75 and 90 percent. It fires once per threshold per page load, which is the behaviour you almost always want and almost never get by accident.

Grind size

Coarser for filter, finer for espresso. The rest is arithmetic.

The interesting measurement question is not whether someone reached the bottom of this page. It is whether reaching the bottom predicts anything you care about. Scroll depth is cheap to collect and easy to over-interpret.

Water

Most of what is in the cup is water, so most of what is wrong with the cup is water.

Try the links below. One leaves the site and one is a file — they push different events, detected by the click handler in events.js rather than by a GTM trigger. Rebuilding one of them as a native GTM trigger is exercise three.

An outbound link · A download (brew-guide.pdf)

Ratios

Sixty grams per litre, then adjust. Everything else is preference dressed up as physics.

Keep scrolling.

The end

If you got here, the 90 percent threshold has fired.

Compare approaches. GTM's built-in scroll trigger would do this with no code. It would also silently keep working after someone deletes this text, which is either a feature or a lie, depending on what you are measuring.