What does afloat mean in green coffee trading?

Afloat means the coffee is on a ship right now - it's left the origin port and is somewhere mid-journey to its destination. Not in a warehouse at origin, not yet available in the UK. It's at sea.

Buying afloat is common in green coffee. Importers and traders will often offer lots while they're still in transit - you commit and pay before the coffee arrives, sometimes without a physical sample in hand. The upside is quicker turnaround than a forward contract; the trade-off is you're making a decision based on pre-shipment samples rather than the landed lot.

If you're offered a washed Ethiopian afloat and you're confident in the importer's sourcing, it can be a good way to get ahead of stock running out. Just factor in the ETA - "afloat" doesn't mean it'll be with you next week.