90 minute boils

[badmajon]

I usually end up with around 6 gallons of wort pre-boil which boils down to around 5 gallons after an hours boil. For the first time I'm doing a 90 minute boil on a Pilsner recipe, what should I do? Just add some water (half gallon?) prior to boil?

Thanks

 

[balazs]

I would sparge more from your mash to get another 1/2 gallon or so to your pre-boil volume.

 

[Homebrewtastic]

Thin out your mash a shade and do a good double batch sparge. You'll get better efficiency and be able to compensate for the extended boil time.