Stuck fermentation in a conical fermenter

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blondeale2001

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Has anyone had a problem with yeast accumulating in the cone part of a conical fermenter and not finishing the beer to a desireable FG reading. If so what can be done to correct this. I aerate my wort and use a yeast started
but can't seem to get the beer to finish.
 

Rivenin

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i doubt it's the conical.
What temp were you mashing? (if all grain)
what temp has fermentation been?
what yeasts were used?
what was the OG?
has this been one recipe that this happened to? or multiples?
what gravity are you at now and what were you expecting to hit?
 

beerbeer95648

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I use a conical exclusively. Early in fermentation the only thing sitting on the bottom of the conical is break material and dead yeast. The active fermentation is happening in the upper part of the conical. As fermentation slows you will get some dropping into the cone, but there is still copious amounts of cells in suspension finishing the fermentation. Even when using highly flocculating yeast like WLP002, I have never needed to rouse the yeast. I would look at you mash regime, yeast strain, temp control, etc. I would also get in the habit of running a forced fermentation along side any ferment.
 
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blondeale2001

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I have been using the conicals for 6-7 batches now. Half were repeat recipes that I have fermented in a glass carboy. The finish gravity readings were always lower in the carboys. I have not paid that much attention to temp seeing that I always ferment in my basement (temp pretty steady in the mid 60's) and have always gotten good finish readings in the carboy. I mash using a Hermes setup and either hit or am above my target OG readings. I always use a yeast starter and have started aerating with a stir stick. In my last beer I used Wyeast Thames Valley 1275. OG was 1.068. When activity trickled down to almost nothing gravity reading was 1.030. I then racked including as much yeast as I could get to a glass carboy and have had steady activity for the last 4 days. I plan on taking a reading in a few days to see we're it is at. I have read that temp is more critical in a conical. When I racked to the carboy I found the yeast packed pretty tight in the cone and it took quite some time and coaxing to get it to move. I appreciate all ideas on this. I am thinking of hooking my pump to the bottom spigot and circulating the wort and yeast back through the second spigot to keep the yeast in suspension like a starter.
 

beerbeer95648

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Thames Valley is not a particularly flocculant yeast, if it is flocculating early it may be due to another stress. When you say aerating with a stir stick, is this been for all the conical batches? It sounds like a possible oxygen issue. Providing a healthy starter and the correct amount of oxygen should yield a healthy fermentation, even with a flocculant strain in a conical. If you did need to rouse, I would forgo the pump and just briefly bubble some Co2 from the bottom port if needed. I used to brew for a larger regional where we had a large yeast propagator that used a small centrifugal pump to circulate wort. It would routinely cause the cells to elongate and change. I would avoid the pump if you could.
 
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blondeale2001

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Thanks
I started using on this batch for aerating a ss rod with 2 paddles attached to the end connected to my cordless drill. I use this before pitching the yeast. I had read that not having enough oxegen in the beginning could be part of my problem. I paid more attention to this last batch because it is an on going problem and it seems that the yeast collected on the bottom way too soon. One thought I had was that the action of the yeast circling in the fermenter (witnessed in a glass carboy) would force the yeast into the cone. The yeast cake when racked to a carboy through the bottom port seem quite tight. I know healthy yeast should still be suspended in the wort but could too many get trapped in the cone.
Other beers that I have kegged from the conical that did not quite reach the FG that I though they should have achieved seem to take up to 3 times as long to get there as beers that I have fermented in a glass carboy. Is it possible that it just takes more time in a conical?
 

zakleeright

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We always used an oxygen tank and stone to get O2 levels up before pitching and have had good results with both ales and lagers, assuming we had properly spun up our yeast to the right pitching rates. I recently heard about a technique the big boys use if the yeast over-flocculates in the conical. They connect a CO2 line to the dip tube, and give it a blast or two. As you can imagine, this blows the yeast up better than the smaller-scale "shake the carboy" method...which I hear comes from the old "taking the keg for a walk around the yard' thing they used to do in days of old when knights were bold...
Cheers
 

beerbeer95648

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Thanks
I started using on this batch for aerating a ss rod with 2 paddles attached to the end connected to my cordless drill. I use this before pitching the yeast. I had read that not having enough oxegen in the beginning could be part of my problem. I paid more attention to this last batch because it is an on going problem and it seems that the yeast collected on the bottom way too soon. One thought I had was that the action of the yeast circling in the fermenter (witnessed in a glass carboy) would force the yeast into the cone. The yeast cake when racked to a carboy through the bottom port seem quite tight. I know healthy yeast should still be suspended in the wort but could too many get trapped in the cone.
Other beers that I have kegged from the conical that did not quite reach the FG that I though they should have achieved seem to take up to 3 times as long to get there as beers that I have fermented in a glass carboy. Is it possible that it just takes more time in a conical?
No, there should be no worry about yeast being trapped in the cone. Normally,within the first 4-8 hr most of your cold break and dead yeast will settle, then your early flocculation cells will drop. Any thermal currents and evolving co2 will keep the rest in suspension. Theoretically, there could be a minutely longer ferment due to the fact the early flocc'ed cells will still ferment at the boundry of the yeast layer and wort, and carboys have more surface area, so maybe. But in reality you should see a healthy ferment in either. It tends to take about 4 days of primary, and 2-3 days for diacetyl rest for my mid gravity beers in a conical. After fermentation though, yeast does tend to pack tightly in conicals vs carboys. I would look at seeing if you could borrow a buddies, or clubs oxygenation set up and try that. Or use the stirrer in conjuction with flushing the conical headspace with o2 from home depot.
 
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blondeale2001

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Thanks guys
I guess some more experimentation will have to take place (temp control, co2 blast, maybe try the recirculation)
I bought 2 of these and it would be a shame not to use them.
 
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blondeale2001

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I did my first experiment last weekend and here are the results. What I did was brew a simple beer (10 lbs 2 row and lightly hopped figuring it wouldn't cost much and I could drink it in the summer highly chilled) I pitched the yeast and gently stirred to make sure they were evenly distributed. I then transferred half to my second conical fermenter. I rigged my pump on the first conical fermenter and circulated the wort for 3 days. The conical with the pump finished about a day and a half faster then the conical with out. Today I took gravity readings from each conical (8 days after brewing) My original OG reading was 1.050.
Both readings from the conicals today were 1.006. I was surprised to see them that low as my target was 1.015. The sample from the conical with the pump had a lot more yeast suspended in the beer then the conical without the pump. Also when draining the yeast and trub from the bottom the conical without the pump was like toothpaste and took some time to thin out were the conical with the pump ran quite easily. The results from this experiment show me that circulating the yeast does not do a thing. This week I have a heat jacket and external thermostat coming and I will brew a beer recipe that did not finish as well as expected in the conical. I will hold temp to what the yeast manufacturer recommends and see if there is a different result for the FG. I wll post the results when finished
 

beerbeer95648

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Just a note, but be conscious of where you place the heating element. I have a heated and cooled conical and went through a few batches that tasted amazing until day 6 or 7, then would change for the worse. This was because my heating pad is pretty low on the cone and once the yeast would start to settle into the cone it would get stressed by the direct heat as the element stayed active until the probe in the center of the fermenter would register the change. The yeast would put off all kinds of organic acids and other funkiness (Wlp001 would through sulfur on day 7-9 under the stress) into the beer at that point. I finally sorted it out by only using the heating element for the first couple days, then shutting it off. Everything has been good since.
 
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blondeale2001

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Thanks. I will definitely keep my eye on that. I planned on using the heater for primary only.
 
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