Controlling Tartness via fermentation

[craigevo]

Anyone know if there is a relationship between fermentation temp and how tart the beer will turn out ?

So iv brewed a belgian dubbel using wyeast ardennes 3522 and its turned out excellent, but a bit tart. not as tart as a saison, but more than expected.

I would like to dial the tartness down a bit if possible. Clearly its yeast related and this yeast has been well documented (in forums, not by wyeast themselves oddly enough) to be a bit tart. Would anyone know if the level of tartness can be driven by fermentation temps - either by going higher or lower ?

I started at 18 deg C and went up to 21 over about a week. I realise some will say this is too cool for this yeast, but Id like to focus on the tartness and not other aspects of high temp fermentations.

Would pitching more or less yeast change the tartness? more or less oxygen perhaps ?

[uncle_bad_touches]

I don't know about fermentation temp, but it could be a side-effect of very high attenuation. my theory is that phenolics and fruity esters produced by the yeast might take on a tart character if the beer finishes very dry. or at least give the impression of tartness without the residual sugar backing it up. please note that I have no evidence to back this up, but it's something else to think about.

what was the FG of your beer?

[cosmo]

Craig,
I think I know what you mean. Are the esters very low? Does it seem to taste dry and harsh but with normal FG? Here is my experience. I hope this helps. I have been dealing with this problem for a while now. At first I thought is was an infection, so I am now impecable with my sanitation. That didn't change anything. Then I thought it was not enought 02, so I increased my aeration. That made it worse and I also got some wet cardboard flavors. So, I reduced my aeration over several batches until I got down to nearly no aeration other than a little splashing as the wort went into the carboy. The dry harsh flavor didn't go away, but did get a little better. By the way my fermentation temperature is controlled (50F for lagers and 68F for ales). The next step was to play with pitching rate. I reduced my pitching rate to about half that recommended by the MrMalty calculator. I have an ale and a lager fermenting now. I will find out in a few weeks if that fixes the problem. Keeping my fingers crossed. Also, I make starters on a stir plate. I don't know if that could influence anything. Maybe I'll try no starter next time. So far I've spent about 9 months and roughly 30 batches trying to fix this. Others with similar experience please chime in.

[craigevo]

OG = 1060
FG=1012
ATT=80%
ABV= approx 6.3%

So, with regard to high attenuation,. yes, 80% is high in my books, but not unusually high, I often get 80% with my belgians and other yeasts eg 1214 (apart from saison) gave me no tartness at all.

Re Oxygen, this could be it - I dont have a DO meter, so have to guess the oxygen flow from my tank. Maybe I overdid it. Iv just got an email from Wyeast saying that too much oxygen can cause the tartness. Actually they said this.. "I would think low pitch rates, high O2 levels and high fermentation temps will help increase acid production"

I have to just turn on at around 5psi and I aearate using diffusion stone for about 2 mins. maybe will try again for only 1 min then.

My ferm temps were reasonably low - so no problem there. And i made a good 2L starter on a stir plate so should not be an issue of yeast quantity. Possibly yeast health, it did ferment a bit start-stop-start.

Wish I knew where to get a reasonably priced DO meter.

[cosmo]

I'm really thinking this is mainly caused by over pitching. Check out this thread where the poster piched on top of a whole yeast cake and it ended up sour.
viewtopic.php?f=19&t=10171
In that thread, bugeater said he thought it was "yeast bite". Also, Wyeast and White Labs recommend a much lower pitching rate (i.e. no starter for beers up to 1.050) compared to the Mr. Malty calculator. I think the starter on the stir plate might be increasing the cell count and/or oxygenation more than we think. I would try either no starter or a smaller starter without a stir plate just to see if that is the problem. That's what I am doing now. I'll post results in a few weeks.