Krausen gone after syrup addition

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frankvw

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I'm brewing a Belgian Tripel using WLP540, and this time I'm trying a staggered fermentation in hopes that it will keep the esters down a little and make for a more controlled fermentation.

I started with the all-grain portion of the wort (OG 1.060) to which I planned to add 1 lb. of Lyle's Golden Syrup (equivalent to DM10 Belgian Candi syrup) after 36 hours, followed by 3 additions of 200 grams each of white cane sugar, starting 18 hours after the syrup and 24 hours apart. Final OG should be 1.079 according to BS3. I'm aiming for 9-9.5% ABV.

When I added the syrup, 36 hours into the fermentation, the Krausen was thick and dense. But at the time of the first sugar addition, 18 hours later, I saw that the Krausen has disappeared completely.

Given the added fermentables which may (but probably aren't) distributed evenly through the wort I don't think a gravity reading will tell me much about whether or not the fermentation is still underway. I didn't take a reading when I added the syrup on the basis of the fact that I was about to change the gravity in any case. Also, my fermenter lid is rather leaky, so the airlock hasn't shown any bubbling to speak of, but the Krausen and the sound of CO2 rising clearly indicated a decent fermentation at the time of the syrup addition.

Does the vanished Krausen mean that my fermentation has stalled and/or the yeast has crashed? There have been no temperature dips. What could have caused the Krausen to do such a vanishing act overnight? I poured in the syrup quite carefully in order to disturb as little as possible.


All insights and suggestions would be appreciated!
 

HB_ATL73

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What temp did you ferment? With a warmer fermentation-ie more rapid ferment the krausen may have just fallen unrelated to the syrup addition. Have you ever used this yeast before with similar experience?

My other thought is just the density of the syrup may have essentially dragged the krausen layer to fall?
Just a thought and no experience to give advice about this
 
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frankvw

frankvw

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What temp did you ferment? With a warmer fermentation-ie more rapid ferment the krausen may have just fallen unrelated to the syrup addition. Have you ever used this yeast before with similar experience?
Well, it's at 26C now which is indeed quite warm (due to the hot weather here at the moment and the fact I don't (yet) have a fermenter fridge.

My other thought is just the density of the syrup may have essentially dragged the krausen layer to fall? Just a thought and no experience to give advice about this
This morning there's no sign of activity whatsoever and the yeast has clearly settled out. So I'm going to rouse the yeast first and, if that doesn't help, repitch. Not sure why it bombed out but it clearly has.

Onward! :)
 

Toxxyc

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Take a gravity reading. Leave the fermenter for a day or two, and take another gravity reading. Krausen, airlock activity and yeast in suspension isn't an accurate measurement of fermentation. Only gravity readings will tell you what the yeast is doing (or not doing, for that matter).
 
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frankvw

frankvw

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Take a gravity reading. Leave the fermenter for a day or two, and take another gravity reading. Krausen, airlock activity and yeast in suspension isn't an accurate measurement of fermentation. Only gravity readings will tell you what the yeast is doing (or not doing, for that matter).
I couldn't agree with you more: gravity readings are indeed the only sure-fire way of monitoring fermentation. Problem is, I'm adding a sugar dose at regular (24) intervals. This sugar is being poured into the wort carefully (so as to avoid aeration and contamination) and not stirred in. So my gravity readings are pretty much guaranteed to be all over the place.

That said, I'm getting the impression that this may be normal behavior for WLP540. I've used it once before to brew a dubbel, and the gravity plummeted to a certain point and then just sat there while the yeast crawled through the remaining gravity points at a glacial pace. Perhaps this yeast simply takes 90% of the time to deal with the last 10% of attenuation. I'll keep monitoring it and post my findings here.
 

Toxxyc

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I couldn't agree with you more: gravity readings are indeed the only sure-fire way of monitoring fermentation. Problem is, I'm adding a sugar dose at regular (24) intervals. This sugar is being poured into the wort carefully (so as to avoid aeration and contamination) and not stirred in. So my gravity readings are pretty much guaranteed to be all over the place.

That said, I'm getting the impression that this may be normal behavior for WLP540. I've used it once before to brew a dubbel, and the gravity plummeted to a certain point and then just sat there while the yeast crawled through the remaining gravity points at a glacial pace. Perhaps this yeast simply takes 90% of the time to deal with the last 10% of attenuation. I'll keep monitoring it and post my findings here.
Stupid question, never having made a beer like this, but can't you hold off on the sugar additions for just one addition? Add the sugar, mix it up by swirling the fermenter around so it's mixed in well, take a reading and then skip one addition, leave the fermenter for 48 hours and measure again just before the next sugar addition? In 48 hours you should see a measurable drop in the gravity, even if it only is 2 or 3 points.

Also, what's your aimed ABV for this beer at this stage? It could be that the high ABV in there already or even the high gravity of the sugar on top of the yeast on the bottom is hampering your fermentation performance.
 
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frankvw

frankvw

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Stupid question, never having made a beer like this, but can't you hold off on the sugar additions for just one addition? Add the sugar, mix it up by swirling the fermenter around so it's mixed in well, take a reading and then skip one addition, leave the fermenter for 48 hours and measure again just before the next sugar addition? In 48 hours you should see a measurable drop in the gravity, even if it only is 2 or 3 points.
Not sure. Common wisdom has it that additions during staggered fermentations should not be made too late in the fermentation, but there don't seem to be any hard-and-fast rules here.

Also, what's your aimed ABV for this beer at this stage? It could be that the high ABV in there already or even the high gravity of the sugar on top of the yeast on the bottom is hampering your fermentation performance.
Well, the OG for the malt-only part was 1.060. The final ABV should be in the 9-9.5% range (well within the limits of what WLP540 can cope with) but that includes 21 gravity points from 450gr. of Lyle's golden syrup (36 PPG) and 600 grams of white cane sugar (46 PPG). The total batch volume is 21L, so we should be somewhere around 7% ABV roundabout now.
 

Toxxyc

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Hmm so it's definitely not the ABV that's knocking out the yeast. Is it not possible that with this current heat waves the yeast ate through the sugars a lot quicker than you expected, and it's literally just slowing down because the sugars are declining?
 
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frankvw

frankvw

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Hmm so it's definitely not the ABV that's knocking out the yeast. Is it not possible that with this current heat waves the yeast ate through the sugars a lot quicker than you expected, and it's literally just slowing down because the sugars are declining?
Possible, but unlikely. The dubbel I brewed with this same yeast took much longer to come down that far (that was not a staggered fermentation.

But I've roused the yeast this morning and taped up the lid of the fermentor, and now there is a very slight pressure build-up to be seen in the airlock, so it looks like fermentation still takes place but very slowly. I'm just going to give it a lot of time and see what it does.
 

Toxxyc

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Good luck mate. This heat is making brewing difficult for us, I know, and that's just the time we're in need of some cold ones. At least my Vienna lager is already on Week 2 of lagering, so it'll be ready for the December holidays - whoohoo!
 

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You really need to take a gravity reading to know where it stands.

It's very possible the fairly small additions of sugar/syrup are being fermented out fast, and won't create much, if any krausen. The CO2 coming out of solution when you add new sugars is normal, due to adding nucleation sites.
Meanwhile, avoid air ingress, oxidizing the beer.
 

IslandLizard

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Gravity is 1.020 as of this morning. So we're not quite there yet. :)
Ah, good to hear!

Once you have an accurate hydrometer reading, you have a solid reference for using a refractometer from now on to keep track of progress, since it only takes one or two drops. You will need to use a refractometer calculator because alcohol is present. Such as this one:
Refractometer Calculator - Sean Terrill
Match the readings between hydrometer and refractometer by tweaking the "wort correction factor."

You can keep sugar doping your beer that way every other day, taking a reading before adding more sugar (and nutrients), to ensure she's still attenuating, until the yeast has called it quits.
You need to add yeast nutrients together with each sugar doping; sugar and Lyle's syrup contain none.
 
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frankvw

frankvw

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Well, this morning we're at about 1.013, six days after the final sugar addition, so gravity is definitely coming down and all seems well. It appears to be a property of the WLP540 to ferment vigorously for a few days and then slow down drastically while it takes a week or more to deal with the final two or three gravity points. Oh well. :) Worse things could happen.
 

Miraculix

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Well, this morning we're at about 1.013, six days after the final sugar addition, so gravity is definitely coming down and all seems well. It appears to be a property of the WLP540 to ferment vigorously for a few days and then slow down drastically while it takes a week or more to deal with the final two or three gravity points. Oh well. :) Worse things could happen.
Belle saison sides the same.... Some yeast just becomes fat and lazy after being fed for some time :)
 
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