How much planting is required to make a difference

[Cazza]

Could I use my honey refractometer to measure in the same way. Presumably it's the same instrument as used on the programme?

Similar, but not the same. Think 'range'.

RAB

You are, of course, completely correct, mine is 10-30.
Cazza

 

[Erichalfbee]

They are cheap enough. Mine reads 12-27% water but it might be fun to get another to play with