[passlaku]

I have noticed that when I use an all MO base malt in my English ales I get a buttery, less than cooked dough taste in my beers.  I thought this was due to unfinished fermentations so I had been doing pretty warm diacetyl rests to give the yeast a chance to work through the compounds.  I was thinking that this was a process problem on my end, but then I heard the interview on CYBI with the MeanTime brewer and he commented that he had a similar problem with MO and now he uses blends of MO with other base malts.  Further, I heard the Jennifer Talley interview (Squaters in Utah) and she commented that she blended MO all the time. 

I have since blended MO with 2 row in a brown (eg 6# MO/3# 2 row) and MO with a couple of pounds of pilsner malt and have not encountered that diacetyl problem again.  I think from here on out, I am going to only blend MO with other base malts and not use it as the sole base malt in my English ales, or whenever I use MO.

Link to CYBI show:
http://www.thebrewingnetwork.com/shows/721

[majorvices]

I have found something very similar to your findings. In fact I used to use MO for 50% of my basemalt for my IPA and I backed it down to about 30%.

That said, I still brew all MO beers from time to time.

[hopfenundmalz]

Do you get this for all MO, or just a particular maltser?  What ones do you use?

[dmtaylor]

I've been using Maris Otter for the past ~10 batches and haven't had any problems with diacetyl at all.  Could be your yeast.  English yeasts are more prone to it.  And once bottled or kegged, give it a few weeks to let the yeast eat up some, if not all, of the diacetyl.

[denny]

Try as I might, I can't think of any quality of malt that would cause diacetyl.

[hopfenundmalz]

Try as I might, I can't think of any quality of malt that would cause diacetyl.

Wort low in valine according to the late G. Fix.  Would recent MO crops have low valine?
http://www.brewingtechniques.com/library/backissues/issue1.2/fix.html

[gordonstrong]

I've never gotten dactyl from Crisp MO and I've used it for 100% of the grist. That said, I often do blend MO with other base malts like Durst Vienna or a US two-row.

[denny]

Try as I might, I can't think of any quality of malt that would cause diacetyl.

Wort low in valine according to the late G. Fix.  Would recent MO crops have low valine?
http://www.brewingtechniques.com/library/backissues/issue1.2/fix.html

Live and learn...thanks, Jeff.

[hopfenundmalz]

Try as I might, I can't think of any quality of malt that would cause diacetyl.

Wort low in valine according to the late G. Fix.  Would recent MO crops have low valine?
http://www.brewingtechniques.com/library/backissues/issue1.2/fix.html

Live and learn...thanks, Jeff.

Jeff Renner had posted the Fix article recently on the club e-mail list.  He was helping out another brewer, and that sort of stuck in the memory banks, old as they are.  Credit Mr. Renner.

[tschmidlin]

If a lack of valine is the problem, it should be easily fixed by using yeast nutrients in your wort.  Try it with your next MO batch and let us know how it goes.  I never have problems with diacetyl, but 2 caveats:

1.  I always use yeast nutrients
2.  I might not be able to taste diacetyl

[majorvices]

Maybe I am the one missing the boat here but what I thought the OP said was he got flavors that somewhat remind him of diacetyl. I have found I can get this in beers with MO. Often times it is very pleasant but that it can sometimes conflict with other floavors in the beer.

For me, I found that the MO in conjunction with the other malts and hops I was using in my IPA had a "sharp" character that reminded me of diacetyl. It was in the back ground, not in your face. Still made a very drinkable beer. Cutting back on the MO made a beer that had a better balance of flavors. Cutting it out completely left a more one dimensional malt character.

In addition to all that, I am toying around with a "single hop, single malt" IPA (All Columbus, All MO with the hops changing from batch to batch) and I found that cutting back on the "single malt" to about 80% made a better tasting beer (to me)..

I guess the thing I should point out is I am making American IPAs, not English. For English those types of biscuity and buttery flavors are essential but they can conflict with American styles.

I also think that back on all the times I thought that English yeasts threw so much diacetyl (and a lot of strains do) but now I believe mroe of that character may have come from the malt.

[gordonstrong]

Caramel and diacetyl can sometimes be confused.  I wonder if that's part of it?  (Not that I get caramel from MO either).

Interestingly, when I was in a sensory lab and tasted the spiked diacetyl sample, it tasted very much like sour cream to me, not butter.  Never tasted that in a beer.

Anyhow, I tend to be a little lenient on diacetyl if it could reasonably be caramel.

[majorvices]

The taste I am thinking of is more butterscotch. I always associated this with diacetyl but have seemed to pick this sort of flavor up from MO (using Thomas Fawcett MO). I should point out I don;t use much in caramel malt in my beers. Like I said, very much a background flavor. Maybe I am getting my wires crossed though and what I am tasting is more biscuit like and I am picking back memories al English style ales. All I know is thats what I seemed to taste and when I played around the percentages I got closer to what I wanted. I could also be crazy.

[blatz]

I use both TF and Crisp MO all the time as the base malt for my America (left of the 'n' just for you Keith ) ales and I think you guys are nuts - no diacetyl cept the rare occasion when I use 1968 Fullers.

[majorvices]

Without a doubt I am nutz.   Still swear I get a biscuity-butterscotch flavor from using MO as a basemalt though. Like I said, its not diacetyl. It just kinda reminds me of diacetyl.

For instance, I brewed an all MO single hopped beer 4 weeks ago. Then, same recipe but used regular 2 row and subbed in some Victory (was out of MO). Beer is very similar and still get some of the biscuit but not the sharp (though subtle) butterscotch type taste.

And I have ruled out infection (if any of you are thinking I am overlooking something) because I am pitching the same strain into an Alt (with obviously no MO) and am not getting any butterscotch-type flavors at all.