Where does the "dark fruits" flavor reference come from?

Mostly yeast, but there needs to be some malt contribution as well.

ETA: take a beer dominated by malt with a really neutral yeast- like Optimator- and it will be mostly toasty/bready/nutty.

take a beer dominated by yeasty contributions- like a Tripel- and it will be mostly spicy/fruity, but will lack that concentrated dark fruit characteristic.

but put them together, where the fruity yeast signature can interact with the dark malts, and that's where you will really get those characteristics. Especially if it's a high gravity beer, where the yeast will essentially gorge themselves and do crazy stuff as a result

 

Yeast and malt, mostly yeast.

 

Yep^ With pale yeast driven beers like Tripels and Golden strong ale you will get paler fruity notes of apple, pear, apricot, and the like. Darker malts react with the yeast differently producing date, figs, prune, raisins etc. As noted in the OP: English Barleywine, Old ale, and Scotch ale use English ale strains which produce fruity esters much like Belgian strains and will have a similar reaction to malt of differing color. If you have ever had English pale ales, they also exhibit a good amount of pear/apple fruits due to the pale color of the beer.

 

In some Belgian and British beers it's from the brewing sugar. Try something like No. 3 inverst and you'll see what I mean.

 

Raisin-y or prune-y or similar dark dried fruit flavors can come either from the malt (dark crystal malts) or from oxidation.

 

Well, it depends. Those dark fruit flavors come mainly from the dark specialty grains. Often they become more intense with age as the beer oxidizes. As Ron Pattinson points out above, darker kettle sugars have those flavors also, sometimes in high amounts (dark Belgian Candi sugar does). Some yeast can produce dark fruit ester, I find those from some British strains. Some hops can have stone fruit flavors too.

Malts - look at the 80L to 120L flavor descriptions. Other maltsters make Special B at around 150L that is very raisiny.
http://www.brewingwithbriess.com/Products/Caramel.htm

Malt flavor wheel.
http://www.weyermann.de/eng/gelbe_seiten_en.asp?go=mr&umenue=yes&idmenue=37&sprache=2

Hop flavor wheel, stone fruit.
https://www.hopunion.com/aroma-wheel/?aroma=Stone-Fruit

Sugars - see the D-180
http://www.candisyrup.com/products.html

Yeast - one of my favorites "dark fruit esters"
https://www.wyeastlab.com/rw_yeaststrain_detail.cfm?ID=189

 

Malts- ayinger celebrator is a raisin bomb for me.
yeast- most belgian quads have the raisin and prune thing going as well. Recently new belgium abbey.
hops- I get stone fruits from alot of the nz hops.

 

Overall, sourcing varies considerably, depending on whether you get dark fruit skins or dark fruit sugars.

In my experience, I've seen different dark fruits come through for different reasons. Yeasts, working with malt and, yes as some here have posted, additional sugars can produce some of the same sugars and flavors you find in prunes and raisins. Dark fruit also includes other less sweet notes, though, characteristically from their skins, and I find plum notes can sometimes be delivered through the combination of certain hops and malts in the absence of large amounts of yeast. I have also had a few sours and aged beers that pick up dark fruit notes based on the barrels in which they age. This frequently comes up in red wine barrel aged beers - you can get quite a bit of plum flesh and skin flavors, as well as the more obvious grape skin element.

 

In my opinion, @FarmerTed has 2/3rds of the answer. Dark Fruit flavors can come from:

· Dark Malts

· Oxidation processes

· Dark Belgian Candy Sugar

It has been my consistent experience in my homebrewing that aging certain beers and the resulting oxidation produced flavors ‘optimize’ the development of dark fruit flavors. For example I homebrewed a Quad which I brewed using plenty of dark malts and dark Belgian Candy sugar, That beer has some noticeable dark fruit flavors when it was ‘younger’ but at around 1 year of bottle aging that beer had prominent dark fruit flavors from the oxidation produced flavors.

Cheers!

 

This thread is awesome. I was going to comment that I usually associate it with minor oxidation, but had never made the connecting that the fruity flavors from ale yeast could come thru that strongly in a stout. Thanks for helping me make that connection BA!!

 

I've tasted this in IPAs too. I've always thought Hop Ottin and Bridgeport taste just like rasins in the finish.

 

Thanks, everyone for educating me. I really enjoy "dark fruit" taste in stouts and strong dark ales and will do so even more with a more "scientific" understanding of the source.

 

I brewed an "American Old Ale" last year that was riddled with problems, such as a severe under-pitch of Nottingham. What came off as harsh/solevent alcohol has transformed into a beautiful bouquet of dark-fruits, which I attribute to a combo of yeast, oxidation, malts, & the maple that was used throughout.

I'm really happy that I waited it out... it just goes to show you that beautiful things come with time.

 

Wonderfully informative thread. I would have attributed it mostly to the esters produced by the yeast, as they tend to give apple/pear/banana notes. It makes sense that the more caramelized sugars in the darker malts would produce more complex esters and the combination would tend toward the raisins and plums. Oxidation of the esters would convert them to aldehydes or ketones and further round out the flavors and smooth things out over time.

 

I agree with previous poster that it is usually malt/yeast combination...

 

I wouldnt stick it to just dark beers either I actually just had my first duvel tonight and thought it had some pear/white grape almost like characters to it. While not a "dark fruit" though it had that grape sweetness and like an under ripe plum or pear.