I ran a FFT on a Belgian Dark Strong for 4 days at room temp (68F +/- 2 F)) and tested a gravity of 1.010 from an OG of 1.100. I used about 300ml of wort to 75ml of Wyeast 1214 slurry. I only aerated during the first hour of the test. This is my first time doing an FFT.
My questions are this: since this is way overpitching, can I really expect the same level of attenuation (90%) out of the batch in the fermenter (the beer is fermenting at room temp under similar levels of oxygenation)? Is there an optimal yeast to wort ratio for the FFT?
Besides an overabundance of alcohol the FFT sample didn’t taste too bad. What kind of taste difference can I expect from the FFT vs. the final product? I was hoping for a moderately high dark fruity ester profile but it was quite low, peppery phenolics were off the chart. There were also very little malty flavors present.
The attenuation difference between FFT and final beer is something that you’ll have to base on experience. I know that some residual sugars work well in a Doppelbock while they don’t work well in a Pilsner. Let the beer finish fermenting. Then take a sample if it tastes too sweet and the FG is still above the FFT FG you know that there are still sugars that the yeast can ferment.
There is no optimal yeast to wort ratio. Just keep in mind that too much yeast, more than 5% for example, might be able to skew the results by bringing in too much of a different OG/FG beer. That beer was your starter beer. But you don’t have to worry about that if you re-suspend the yeast sediment with the wort to be tested before you pitch the yeast and keep a little bit for the FFT.
Don’t use the taste as an indication of the beer taste. I do taste my FFTs, but only out of curiosity.
I think I may have heard it called a Forced Ferment Test somewhere.
I used the dregs of a quart jar where I had stored a slurry and the amount of yeast ended up being a liitle bit more than I had anticipated. In the future I will try to get a little more wort to make it easier to obtain the FFT sample. Grabbing a bunch of the cold break and letting it settle out in a large pitcher works pretty well for getting wort samples and doesn’t take away from the final beer.
I think they can be two different things actually, at least from what I’ve deduced from threads on the ProBrewer forums. The way I read it was that the ‘Forced’ test was to help determine possible infection\flaw sources, whereas the ‘Fast’ test is used primarily for determine potentially finishing gravity.
That’s how I have been seeing this as well. The “forced ferment test” is also known as “wort stability test” which is a less confusing name. Fast ferment test also works well with the German name for this test: Schnellgaerprobe (literal: fast-ferment-sample).
After two weeks I measured a gravity of 1.013 and racked into a carboy for aging. Sample tasted pretty good. Even with 12%+ alcohol it did not have the “hotness” or “alcohol” type flavors.
The FFT was pretty close and the gravity may yet drop a point or two.
I myself, finally remembered to take a sample for FFT when racking into the fermenter last night. Brewed a big Old Ale (1.091), so interested to see where it ends up and how close the rest of batch gets to that number. Being a big beer, it will be nice know where it should end up, so after 3-4 weeks I’m not stuck wondering ‘will it go lower?’
Apologies for the thread drift, but does anyone have experience using wine yeasts to do a FFT?
I had been under the impression that Belgian beer yeasts and wine yeasts were genetically, possibly, not all that distant from each other. And most wine yeasts have very high levels of alcohol tolerance. So I thought I could use a dry wine yeast to do a FFT on a dunkel. I always have lots of extra wine yeast around, and it was my first go at using 100% munich malts and so wanted to monitor the ferment.
The FFT stalled at 1.020; the dunkel fermentation (with WL833) is now at 1.016 and appears to still be going. I think I did the procedure correctly, so this appears to be a simple case of the wine yeast not liking those munich malts. The OG was 56 so the alcohol level is well within the tolerance for this Lalvin yeast (k111 I think).
bread yeast is S. cervesiae (sp?) which is the ale yeast species. But I don’t exactly know what species wine yeast is. Possibly S. bayanus, if I remember correctly. Lager yeas is actually a hybrid between these two yeasts which means that you inclination to use wine yeast is correct. But I’m surprised about the difference between the FFT and the actual fermentation which you are seeing.
Yes, wine yeasts are generally S. bayanus, lager yeasts are currently classified as S. pastorianus (used to be S. uvarum or S. carlsbergensis). Yeast taxonomy gets ugly, don’t get me started
I’m sure it would work, but the results wouldn’t be applicable to the fermenter with the beer yeast. AFAIK no wine yeast strains can ferment maltotriose, so the FFT gravity would likely be higher than the main batch.
If bacteria can mutate to use a man-made molecule like nylon as a carbon source, I’m sure yeast can develop an enzyme for maltotriose. And Lenski’s work with bacteria in citrate shows they can mutate to use that.
The key will be to give them an abundance of maltotriose, so that as soon as one cell mutated to use it it would have a large competitive advantage over the other cells in the culture.
Thanks for the replies and good info everyone. I never would’ve guessed that bread yeast could act as a delegate for beer yeast better than wine could.
I found numerous sources putting the percent of maltotriose in beer wort to be around 13 - 14% (Malting and Brewing Science says 13.6% is typical). I did not see any info that indicated that Munich malts were an exception to this number. Briess puts most of their LME’s (including the Munich) at 13 or 14% maltotriose. Their black malt LME was considerably lower at 8%.
So I guess I could put a rough FFT for this test at 20 - (56 x .136) => 1.012 or 1.013. roughly.
To quote from Danstar’s website:
Beer yeast usually can ferment maltotriose, most wine yeast cannot. To me there is no big deal if the yeast cannot ferment the maltotriose. The mashing procedure can minimize the amount of maltotriose present in the wort and the unfermented maltotriose just gives you more body, mouth feel and perhaps a slight sweetness.
Turns out, this is one of two main ways to tell wine yeast from beer yeast. Here’s the other, also from Danstar:
1. Phenol off flavor or POF test. Most beer yeast are POF negative. A few of the wine yeast that I have tested were POF positive.
FWIW, the FFT with wine yeast tasted unpleasantly familiar; it reminded me of bad home brew I had back in the 1990s, and which was the reason it took me a long time to try out this hobby! A bit like apricot bread that was funky.
