60 v 90 minute boil?

[kegging]

What's with trouble doing a 3hr boil for their imperial stout

[Hop Bomb]

15 points low on their pre boil gravity probably  .   Or looking for tasty caramelisation.

[Slev]

If you're using lots of pilsner malt in your grist then a longer boil will help drive off the DMS. Pilsner contains more SMM (precursor to DMS) than Pale Malt hence the extra boiling time.

Yep. Thats the thing. Will be interesting to see if I have off flavours. 20 min boil and warm fermentation (and maybe under pitching - used 1 pure pitch without starter in 13l at 1.050)... So if there are off flavours, may be hard to pin down the cause. (not sure I'd be able to recognise DMS flavour anyway)

Just an update.
So. Kegged the this , adding gelatin and carbed over a week. On Wednesday pulled the first pints, which were cloudy,  due to the gelatin, but distinct banana smell. Discarded the first 2 pints. Tasted the third. Bananas. Googled looking for some salvation, but all pointed to Esther's. Disappointed.
But pulled a pint tonight. Crystal clear, and no bananas! It has turned out very interesting. It's a Pils, but with fruity overtones. Happy with it. Definitely not a traditional pils, but a nice beer. Would be very happy to order another in a pub. Suspect that it will mature over the next while, and the fruity(and sweetness) will blend some what.
But overall, don't detect any dms (from what I think it is or should be). No banana! Happy as it is. Certainly interesting experiment.
Will report back in a few weeks again