Coffee

Espresso issues (and solutions)

Fast extraction/channeling

1. Grind finer. Go as fine as to choke the machine and proceed from there
2. Beans are possibly stale. Get fresher ones.
3. Increase dose
4. Check correct tamping

Initially slow extraction, then very fast

It may be channelling. Try grinding slightly coarser to avoid the pressure to create channels a few seconds into the shot. This should rebalance the extraction.