[Pawtucket Patriot]

I brewed a witbier yesterday with just over 50% flaked adjuncts (~40% flaked wheat, ~10% flaked oats).  My efficiency was 69%, well under what I normally achieve (I usually hit 80-85%).  I didn't mill the flaked adjuncts because, well, I never have before and my efficiency hasn't suffered.  But this was really the first time I've used such a high proportion of adjuncts.  I'm wondering if I could expect a significant efficiency boost if I milled the flaked adjuncts to increase their surface area.  I can't think of anything else in my process or in my stats from the session that would lead to such a low starting gravity. 

To the extent that it would help to know my process/stats, here goes:
I milled the barley malt on my regular setting; this setting hasn't been adjusted in probably 100+ batches.  This was a single infusion witbier that was mashed at 154 for 60 min.  My mash pH was ~5.3-5.4.  I batch sparged and collected 7.5 gallons pre-boil wort.  I boiled for 90 minutes and ended up with a post-boil volume of 5.4 gallons.  S.G. of the post-boil wort was 1.040 (I was shooting for 1.051).  Grain bill was 4 lbs Pils, 3.75 lbs flaked wheat, 1 lb flaked oats, .30 lbs acid malt.

[rabeb25]

Anytime I have milled adjuncts, I ended up with a wicked stuck mash.

[onthekeg]

I think some of your efficiency issue would be having more flaked grain than base malt.  The most I would do would be 50/50, but you were over that. 

[Pawtucket Patriot]

Tim,

So you think it might be a lack of diastatic power in the mash?  That would make sense, but it seems like the pils should have at least converted its own weight in adjuncts.  I'm not sure that the relatively small percentage of adjuncts that exceeded the weight of the pils explains the efficiency drop.  I could see it causing a drop of a few points.  But 16 points?  I'm sort of at a loss to explain...

edit: I just calculated that the average diastatic power of my mash was 48.6 degrees Lintner, which should have been more than enough to convert everything.

[onthekeg]

It may have had enough diastatic power to convert, but not in 60 minutes.  I don't believe that its a linear equation as it converts, it will convert real fast in the first 30 minutes, but as the enzymes become less and less, it will take longer to get complete conversion.  In my experience.

[Pawtucket Patriot]

It may have had enough diastatic power to convert, but not in 60 minutes.  I don't believe that its a linear equation as it converts, it will convert real fast in the first 30 minutes, but as the enzymes become less and less, it will take longer to get complete conversion.  In my experience.

How long would you mash the grainbill I described in the first post?  90 minutes?

[onthekeg]

Matt,
With that high of a adjunct ratio, I would have gone at least 90 minutes provided you can keep the mash at a decent temp.  I guess time will tell, but you probably will have a starch haze but in that beer you probably won't care anyway.
It just may not keep as well as a fully converted beer.  It would have been interesting to see what would have happened if you decocted a thick portion of the mash and boiled it and added it back Hochkurz style at 158 and let it rest a bit.  The amylase may have got more active and chewed away at the end which may have upped your efficiency and gave better conversion.

Oh well, theres always next time right?

[Pawtucket Patriot]

Oh well, theres always next time right?

Next time, as in this coming weekend. 

[onthekeg]

Oh well, theres always next time right?

Next time, as in this coming weekend. 

That would be pretty cool, then you could compare the beers later on and see if there was a difference or not!