[Iliff Ave]

Should I expect a reasonably different in attenuation figure for a 45 minute mash @ 154F vs 60 minutes at the same temp?

I should complicate anything by decreasing my normal mash length for a strain that I have not used and am unfamiliar with. My only reasoning behind this is to speed up this particular brew day with a 45 min mash and boil.

[dilluh98]

I doubt it. It depends on the recipe of course but I recently made a mild with a 30 min mash + 30 min boil and it's every bit as good as previous milds I've made with traditional 60 min mash + 60 min boil. I just wanted to see if I could pull off a short brew day mid-week, after work, while also prepping dinner. It got a bit hectic at times but I know it's possible if I want to make it happen.

I think I remember dave saying he does almost all of his mashes now at 45 minutes instead of the full hour. For me, on a weekend, I'm not usually sweating the extra 15 minutes because that hour is spent baby wrangling and/or doing house chores. Gotta multi-task in my zoo-like life.

[reverseapachemaster]

For most beer styles, recipes and equipment there is not going to be a cognizable difference between 45 and 60 minutes. For drier styles the difference you get out of those fifteen minutes could be the key to the right level of dryness without unloading sugar in the kettle or later.

[Iliff Ave]

Just doing an APA so it sounds like it shouldn't be an issue. Too late now...

EDIT: Looks like I am about 6 points low on my OG...bummer...not that it's necessarily related to the short mash...

[dmtaylor]

I'm a bit of an expert on 45 minute mashes (actually I usually do 40 minutes), I've been doing it for 10 years on almost 100 batches...

The shorter mash time won't hurt your efficiency or attenuation by any statistically significant amount.  I mean, we're talking like 0.001 gravity point and 1% attenuation difference as compared to 60 minutes.  You just aren't going to notice at all with well-modified 21st century malts.

If you were to use highly kilned dark Munich as your base, or a buttload of adjuncts, like 40% or something insane like that, then it might make a bigger difference.  But otherwise, no.