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General Category => Yeast and Fermentation => Topic started by: edward on January 13, 2011, 12:48:52 PM

Title: Forced Fermentation Test
Post by: edward on January 13, 2011, 12:48:52 PM

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.
Title: Re: Forced Fermentation Test
Post by: Hokerer on January 13, 2011, 03:40:15 PM
If you mean Fast Ferment Test, then Kai has a good article on his wiki about it...

http://braukaiser.com/wiki/index.php/Fast_Ferment_Test (http://braukaiser.com/wiki/index.php/Fast_Ferment_Test)
Title: Re: Forced Fermentation Test
Post by: Kaiser on January 13, 2011, 03:51:54 PM
hokerer, Thanks for posting the link.


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?

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.

Quote
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.
Don’t use the taste as an indication of the beer taste. I do taste my FFTs, but only out of curiosity.

Kai
Title: Re: Forced Fermentation Test
Post by: edward on January 13, 2011, 04:21:53 PM
If you mean Fast Ferment Test, then Kai has a good article on his wiki about it...


I think I may have heard it called a Forced Ferment Test somewhere.



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.



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.

.
Title: Re: Forced Fermentation Test
Post by: gimmeales on January 13, 2011, 07:43:52 PM
Quote
I think I may have heard it called a Forced Ferment Test somewhere.

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.
Title: Re: Forced Fermentation Test
Post by: Kaiser on January 13, 2011, 07:54:03 PM

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).

kai
Title: Re: Forced Fermentation Test
Post by: edward on January 14, 2011, 12:15:14 PM

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).


Consider me edumacated!
Title: Re: Forced Fermentation Test
Post by: Thirsty_Monk on January 16, 2011, 09:18:48 PM
I was always curious about FFT but have never done it.
I should start doing this one of these days.
Kai thank you for awareness.
Title: Re: Forced Fermentation Test
Post by: edward on January 24, 2011, 12:36:57 PM
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.
Title: Re: Forced Fermentation Test
Post by: gimmeales on January 24, 2011, 04:37:16 PM
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?'
Title: Re: Forced Fermentation Test
Post by: seajellie on January 26, 2011, 02:22:56 PM
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).

Kai recommends using bread yeast.
Title: Re: Forced Fermentation Test
Post by: Kaiser on January 26, 2011, 03:37:44 PM

The FFT stalled at 1.020; the dunkel fermentation (with WL833) is now at 1.016 and appears to still be going.

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.

Kai
Title: Re: Forced Fermentation Test
Post by: tschmidlin on January 26, 2011, 06:12:44 PM
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 :)
Title: Re: Forced Fermentation Test
Post by: a10t2 on January 26, 2011, 09:34:49 PM
Apologies for the thread drift, but does anyone have experience using wine yeasts to do a FFT?

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.
Title: Re: Forced Fermentation Test
Post by: Kaiser on January 26, 2011, 10:15:46 PM
AFAIK no wine yeast strains can ferment maltotriose, so the FFT gravity would likely be higher than the main batch.

That would explain the difference he is seeing.

Kai
Title: Re: Forced Fermentation Test
Post by: tubercle on January 26, 2011, 11:23:57 PM

AFAIK no wine yeast strains can ferment maltotriose....

  Hmmm....

 I wonder if they could be trained?

Make starter-size batch after batch after batch and maybe over time they would mutate.

I wish I had more time on my hands.
Title: Re: Forced Fermentation Test
Post by: tschmidlin on January 26, 2011, 11:45:06 PM

AFAIK no wine yeast strains can ferment maltotriose....

  Hmmm....

 I wonder if they could be trained?

Make starter-size batch after batch after batch and maybe over time they would mutate.

I wish I had more time on my hands.
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.
Title: Re: Forced Fermentation Test
Post by: tubercle on January 26, 2011, 11:46:51 PM

AFAIK no wine yeast strains can ferment maltotriose....

  Hmmm....

 I wonder if they could be trained?

Make starter-size batch after batch after batch and maybe over time they would mutate.

I wish I had more time on my hands.
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.

 Tubercle has work to do ;D
Title: Re: Forced Fermentation Test
Post by: tschmidlin on January 26, 2011, 11:48:49 PM
Tubercle has work to do ;D
Lenski's work was surely funded by a grant, you might want to start writing one :)
Title: Re: Forced Fermentation Test
Post by: seajellie on January 27, 2011, 03:04:40 AM
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.

Title: Re: Forced Fermentation Test
Post by: Kaiser on January 27, 2011, 03:43:01 AM
So I guess I could put a rough FFT for this test at 20 - (56 x .136) => 1.012 or 1.013. roughly.


Nice analysis, but I think you'll have to work with real attenuation and not apparent attenuation.

The apparent attenuation in your FFT is 64% which meas that 53% of all the sugars fermented (real attenuation). Now add another ~13% for the maltotriose and you'll get a real attenuation potential of 66% for the beer. Calculating this back to the FG gives you 1.011.

Kai
Title: Re: Forced Fermentation Test
Post by: seajellie on January 27, 2011, 01:40:19 PM
Right you are Kai, of course. I was aware last night that apparent/actual attenuation would affect the numbers, but I didn't think it would be by as much as 0.002 since we were dealing with only a portion of the OG. I was too uninspired (or lazy) to do the math properly, but that's an important difference considering the purpose of this exercise. Cheers!

I was also thinking other (unknown) factors could affect the result so that stopped me from going further. One possible factor being maybe WL833 can deal with a small portion of the higher saccharides better than wine yeast. I know most of these won't get metabolized at all. And a bigger one was this odd fact I found on Danstar's site too. And those wishing to train yeast in their spare time may be interested in this wine yeast which acts very much like a beer yeast. At the risk of getting anyone started on yeast taxonomy....

There is one very famous wine yeast that is both POF negative and can ferment maltotriose. It is probably the largest selling wine yeast strain in the world. It is Lalvin K1-V1116. It was used in a beer kit for several years and it was the yeast of choice in a Canadian brew pub for several years.

That threw me, because my memory was telling me that I had used a yeast with a very similar number to that -- a possible relative, if not in fact that same yeast. Which only takes me down all sorts of new roads.

all in all, I think I'll just use bread yeast next time like Kai  suggests  :)
Title: Re: Forced Fermentation Test
Post by: a10t2 on January 27, 2011, 03:54:16 PM
There is one very famous wine yeast that is both POF negative and can ferment maltotriose. It is probably the largest selling wine yeast strain in the world. It is Lalvin K1-V1116. It was used in a beer kit for several years and it was the yeast of choice in a Canadian brew pub for several years.

Ooh, good find. Looks like that one's actually S. cerevisiae: http://www.lalvinyeast.com/images/library/ICV-K1_Yeast.pdf

Might be fun to try it out in a beer wort.

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.

And for best results, apply regular doses of ionizing radiation.