Efficiency drop UK >NZ

[Toast]

Hello Folks,
I started brewing in the UK in April 2009 and had an efficiency of 85%.
I wasn't treating the water which was pretty hard (Farnham)
I was buying pre-milled malt from the Farnborough Homebrew Shop. Warminster Maris Otter was the muscle malt.
I moved to NZ in December last year and my efficiency has dropped to 65%
Water is pretty alkaline, I had not been treating it.
The malt is un-milled (Baird's MO shipped from the UK) and I've milled it with two different Barley Crushers (one a friends one my new one)
I've treated the last brew using CRS and DLS having tested the alkalinity with an aquarium kit. Made no difference.

Anyone got any clues why it has dropped? It's consistently 65% now :hmm:

 

[Muddydisco]

"I started brewing in the UK in April 2009"

"I moved to NZ in December last year"

Could it be something to do with the fact you moved to NZ before you started brewing :wha:

 

[Toast]

smart *rse!

 

[jamesb]

Two things come to mind immediately - the potential extract of the grain, and the crush.

 

[Toast]

The crush is what I thought. A fellow brewer in nz is using the same grain and is also achieving 65%...wonder if Bairds provides less potential extract.
Brewed Big Kenny III today - that's the one with more hops - went pretty smoothly aside from the hopstopper coming adrift in the kettle! filtered through sanitised swiss voile...BK looked pretty good in the FV, can't wait to try it.

 

[Vossy1]

Another vote for crush size here. I had some malt milled medium, and I and a few others noticed a drop in efficiency over fine ground.