Stirplate for Carboys?

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UselessBrewing

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Occasionally I will make a big beer (Above 1.060) for special occasions, family outings, or just for myself. Recently I made the third rendition of a Scotch Ale which came in at 1.109. My procedures during primary fermentation change a little for bigger beers in that I roust the yeast twice a day to keep them going strong...

So I was thinking I have a Stirplate for my starters, why not for the carboy? I usually turn the stirplate up fairly high in order to get good aeration thereby increasing yeast production. I'm not talking about that kind of speed, just enough to move the beer/yeast around a little and keep the yeast in suspension during primary fermentation. I'm not worried about having too much yeast in suspension because these types of beer usually take 3-4 months to age. And they are usually in the primary for almost a month then in the secondary for a month.

Does Budweiser, Miller, or Coors (BMC) move their beer around during primary fermentation?

What are your thoughts?

Cheers
Preston
 
I've thought about the same thing, but I don't really see much benefit. You should be pitching enough to keep them in suspension anyway, just because of the natural churning produced by the rising co2. I've very rarely ever gotten a stuck fermentation to restart just by stirring, which makes me think that premature flocculation isn't really a problem.

I don't think BMC breweries do this; they actually go out of their way to enhance speedy flocculation with the beechwood chips at budweiser. They're not aging their beers for 3-4 months, and they filter them. But then, maybe I'm wrong, but I don't remember seeing anything about rousing fermentation when they did that "How Stuff Works" on beer a little while back.
 
When growing microbes up in the lab, I almost always move them around somehow - usually shaking or stirring with paddles from an overhead motor. If I am in a 10 L vessel though (which is about 2.5 gallons) I also blow in air (or oxygen for very high cell densities). A stir plate that moves 5 gallons around fast enough to keep it aerated is going to need a powerful motor. The cheapest I found with a very quick peek in my catalogs was over $1,000.

Note: you also do not want to be stirring after the yeasts have finished growing anyway. Oxygen during the fermentation stage will (a) prevent the formation of alcohol and (b) cause off flavours.
 
I am not a yeast expert, but if you had a nice size starter going into it then i do not think there would be too much benefit.

But I say build it and do a side by side comparative. 1 batch with the stir plate, 1 batch that you stir by hand once in awhile, and 1 batch that you did nothing to.
 
You, more than likely, will do nothing more than create off flavors from the presence of Oxygen. Your best bet is just make the biggest starter that you can.
 
When growing microbes up in the lab, I almost always move them around somehow - usually shaking or stirring with paddles from an overhead motor. If I am in a 10 L vessel though (which is about 2.5 gallons) I also blow in air (or oxygen for very high cell densities). A stir plate that moves 5 gallons around fast enough to keep it aerated is going to need a powerful motor. The cheapest I found with a very quick peek in my catalogs was over $1,000.
Note: you also do not want to be stirring after the yeasts have finished growing anyway. Oxygen during the fermentation stage will (a) prevent the formation of alcohol and (b) cause off flavours.

The purpose I envisioned was not to aerate (that will be done in the beginning) but just keep the yeast in suspension. Maybe a 4" stirbar and a motor that travels slow enough to keep the wort moving and keep the yeast from flocculating, and possibly getting that last few points of FG.

The size of the starter has not been an issue in the past, partially because I usually pitch big beers on a yeast cake, or make an adequate starter per Mr.Malty.

Cheers
Preston
 
I'm no expert, but I think if you adequately aerate and pitch a big starter is the best bet. It is my understanding that the main limitation on the FG of a big beer is the yeast strain's tollerance to the build up of CO2 and alcohol.
 
Somewhere on this forum is a pic of carboy with a vortex in it on a massive stirplate.

I also vote for the giant starter.
 
Then consider the shape of the conical. I read some where that its shape was designed to encourage the yeast to travel up the center and back down the out side and act as a natural mixing system.
mmmmmmm....a bit off the track maybe but that's what happens during lunch break
 
Note: you also do not want to be stirring after the yeasts have finished growing anyway. Oxygen during the fermentation stage will (a) prevent the formation of alcohol and (b) cause off flavours.

Methinks your logic is flawed.

In a carboy with an airlock that has been fermenting and creating CO2, where's this oxygen suddenly coming from?

If he's stirring it just enough to rouse the yeast, he's not magically creating oxygen under a blanket of CO2...not to mention that the stirring will cause the fermenting beer to release even more CO2...
 
Glad I found this thread. I have been tinkering with the idea of doing this in my pressurized fermentation setup, since no oxygen is present after primary fermentation.

I read that the beechwood in Bud (and older German lager breweries) is used to create a larger surface area for the yeast to mature the beer faster, as well as allow easier/faster filtration off the yeast. I have even read where some breweries pass green beer through specialized containers, allowing a large supply of yeast inside the vessel to "instantly mature" the new beer (as they wrote). While I am not into the instant beverage thinking for my beer, the faster maturation of a beer due to increased contact with the yeast seems very promising with my type of setup.

I was just talking on the chat, and the others thought this might also be a great way to reduce the total time needed for yeast to clear up a beer. I am going to do some experiments and try this approach. The first experiment is to fill my "keggle" boil kettle with spent yeast from my fermentor and the rest with water, let it sit a couple of days to repack to the bottom, and then apply stirring via a stir bar mounted magnetically on the sidewall. The stirrer mounted on the outside of the kettle would hold the bar in place until its needed time. This should tell me just how much yeast would get re-suspended from the normal sediment on the bottom of my primary fermentor (hoping not a lot). I know there would still be yeast in suspension, in a secondary phase beer, that would have not fallen until the crash cooling phase. If it doesn't stir the whole shebang up, then it's a go for the second stage of experiments.

Second stage consists of, in my case, a stirred primary after fermentation has completed and during "my" secondary/carbonation phase. This is up for debate on when I will quit stirring and start my crash cooling phase. I am hopeful that I can still do my normal 3 weeks in the closed-system primary fermentation keg, and then move under counter-pressure into my secondary/serving keg for a week of room temperature aging before moving into the kegerator for my ales. Once I get into lagers, the periods and processes will change a little.

Although it sounds like something new, the theory is the same as the beechwood chips (without the filtering that they do). Suspend the yeast, mature the beer, crash cool, then rack counter-pressure as I do now.:rockin: I will do a full write-up of my experiments and all procedures for all who will be interested. I really hope this is something that can help attenuate higher gravity beers more (even a couple of points), as well as mature a little faster (even if it is only a slight amount). Remember, I'm doing it on ales but am practicing for lagers. Am I crazy? I like to think so!:drunk:
 
i think trub is going to be your major problem here. you would have to be able to keep the yeast in suspencion while leting the trub settle. i may be off here though?
 
No, you're not off. That is one of the things the first experiment will show one way or the other. Either way, the crash cooling period where you settle the yeast out should accomplish dropping everything out of the beer when it is time.

I was worried about off-flavors from it being stirred up, but the consensus was this wouldn't be a problem since the stir bar would be mounted and spinning on the side of the fermentor and not the bottom. If the stir bar were on the bottom, it would have a hard time getting started from all the sediment packed in down there. The off-flavors from re-suspending the yeast were also not seen as a worry. That yeast packs pretty good, and I would most likely just be stirring what would be carried over to a secondary at this point anyway. One recommendation was to do the stir bar in a secondary/lagering type keg and then cold crash, so this may be what I end up doing.

After a first beer is done the first way mentioned we will see, and that is only if the first experiment doesn't re-suspend the majority of the post primary phase sediment (this is the kettle experiment with old spent yeast test). Someone could speak up with evidence that "rolling" a keg filled with sediment and then crash cooling to drop the yeast would be bad, and I would appreciate that evidence greatly prior to trying anything. I just don't feel anything like this would be anything but a clarity issue at worst (I still reserve the right to be wrong on this though :)).

After washing yeast and letting it pack down a day in my fridge, it takes a lot to re-suspend the yeast so.... Keep the comments coming though, stir bar in a carboy might not be a bad thing.
 
I'm bumping this back up to see if anyone has any more discussion to add. A stir bar in the primary seems like a good idea to me.
 
Bel Art Products Inc. has a Drum Stir Plate. price is $1,793.25 Each.
The cost to manufacture this thing is like less that $50.00 complete with the housing knob and paint in a cardboard box.

It is nothing but a huge Neodymium Iron Boron magnet 2"x1"x0.5" mounted to a little fractional horsepower motor driven through a rather inexpensive speed controller. They used to use an Alinco 5 magnet.

You can easily build a stir plate to drive a large magnet spin bar in a carboy.

The real challenge you'll face will be magnetic coupling.

The bottom of the inside of the carboy is thick and thickness is your enemy. Magnet coupling drops off on a log of the distance.
So you will need a very large gauss field to overcome the thickness.

Then your plate will have to have a sweet spot on it just big enough to let the magnet rotate and also be thin enough to let your magnet be as close to the upper surface as possible. The rest of the plate will need to be heavy enough to support the carboy.
The thinner that sweet spot is the better 'cause thickness (distance) is your enemy.

Another issue will be the geometry of the carboy bottom. It's convex. This will interfere with coupling because the magnetic spin bar will have a tendency to slip away. Which also argues for a really robust coupling.

So I'd suggest trying it with the hugest honkin Rare Earth magnet you can lay hand to. Maybe 3" long x 2"wide x 1" thick. Bear in mind that if your driving magnet is too big you might just grab the spinbar by one pole and whirl it around til it decouples.

Then buy the biggest spinbar you can. The above named company sells what looks like a little football. It's a really good spinbar. Probably the best available. 371300003 Egg-Shaped Spinbar® Magnetic Stir Bar 3 X 3/4
 
So as I see it, that's 3 solid reasons to try a bucket fermenter instead of a glass/plastic carboy (and this is coming from a guy with 3 glass vessels)...

1. Flatness of the bottom vs. convex carboy
2. Size of the magnet required (you're not going to fit anything bigger than 1" square into a glass neck).
3. Closer proximity to the stir plate itself.

How stupid would it be to have something that just agitates the whole fermenter like one of those coin operated beds you always see in the movies? Maybe time for a DIY baseplate connected to the top of a power sander hooked up to an electric timer so it's not wiggling all day long?
I'm not particularly adept at hydrodynamics, feel free to call me stupid. In fact, let me do it...that's stupid.

I'll probably just stick with shaking the damn thing every time I walk past it, but it's fun to think about this stuff.
 
Shaking has worked wonders for me to accelerate maturation/cleaning up. I did an experiment with my boil kettle and stir plate I built. I used a little pill stir-bar and it created a vortex in the kettle full of water. I ferment in a Sanke so this was to test that theory. Operation with sediment would probably be a different story, but the water test with the smaller bar worked well. I need to buy one of those football shaped bars. They should work in almost anything. I am interested in finding out more from you guys talking, so I will stay tuned. For now, turning the keg upside down and shaking it works just fine.
 
One of my brewing friends is a Microbiologist.(ok, two of the brewing guys are, but that's to be expected, for now we will just focus on the one). He has a great explination of what you are looking for in a starter, and why I think a large stir plate would revolutionize home brewing. As you can tell, i've been thinking about this for a while too.

"OK, OK, i guess I can try to make some sort of contribution to this discussion here. I think there is a bit of confusion here about the yeast that come in the liquid from the homebrew stores, either smack packs or vials. There are two key terms everyone should be aware of and the differences between the two. One is yeast viability and the other is yeast vitality. Viability is easy to define as it basically describes the overall number of yeast cells that are alive. If you were able to count the cells under a microscope and then plate out a small, countable number of cells onto an agar plate the viability of the yeast would be the number of cells that actually form a colony as compared to the number of cells you plated. Vitality on the other hand is a more ambiguous term that describes the overall health of those viable cells. In brewing terms it could be described as how fast the cells could divide and as well as how efficient they are at fermenting sugars. Cells will have high vitality if they have sufficient fermentation precursors stored up. For example, oxygen is required to build up sufficient cell wall components prior to fermentation because during fermentation (in the absence of oxygen) these cell wall components are not synthesized and are depleted upon every cell division until a lower limit threshold is reached and the cells can no longer divide thereby decreasing fermentation efficiencies. So, even before you pitch your yeast, you can easily have a population of cells with high viability but low vitality if not properly prepared. For example, the older a vial or smack pack is the lower the viability is as well as the vitality, but I think that vitality drops off much faster than viability over time.

So back to the question of starters. Creating a population of cells with high vitality requires that you give the yeast the proper nutrients that prime them for fermentation. I think this is where Wyeast smack packs are superior to White labs yeast vials. When you pop the smack pack you release vital nutrients to the yeast so the somewhat dormant yeast greatly increase their vitality. There is no way to do this for White labs unless you use a starter to wake them up. A starter is useful for both because depending on the starter technique you use you can greatly increase the total number of viable cells while at the same time increase the overall vitality of the entire population. The most important component for the starter is oxygen. Why force the cells to start fermentation in a starter when you are just going to pitch them into an oxygen rich wort, which inhibits fermentation, only to have that oxygen quickly depleted requiring a switch back to fermentation? If you use a stir plate to add oxygen continuously to the starter you can greatly increase the overall numbers of cells in a smaller volume of starter wort. These cells will have built a nice ample store of the cell wall components required for proper attenuation of your beer. If you prefer the more traditional method of a still starter you will be better off if you give the starter a stir twice a day or so to scrub out the built up CO2 and introduce more O2.

I think a better place to add things like yeast nutrient (i.e. Servomyces) would be at pitching or a day or two into the fermentation. The yeast nutrients add things like metal ions required for enzyme function as well as free nitrogen required to synthesize these enzymes. Adding this to the fermenting wort of your beer will give the yeast a boost as they use up the limited nutrients that come from the malt.

I use a stir plate for my starters because I don't use smack packs or vials, but am instead building up my population step by step from literally a single yeast cell. I need the extra oxygen to get to the proper number of viable cells with the added benefit of also getting high vitality. Either way, though, if you are using store bought liquid yeast, make sure the package is as close to the manufactured date as possible and if you have the capability, use a starter of any technique (stir plate of otherwise) to increase cell vitality.

Wow, is that enough of an explanation? Cheers!"

Those are his words, and a fantastic break down of what happens in a starter. In the fermenter, you would just be looking for constant movement, just enough so that the yeast is always in contact with the wort. Oxygen would not be added, as the yeast, and your wort would already have as much as they need. I've very curious to try this, and have bought a large stir bar, and i'm going to use it in my primary fermenter on my regular stir plate. I'm hoping this would take care of those tricky Belgian yeasts, or a great way to get those stuck fermentations going
 
So as I see it, that's 3 solid reasons to try a bucket fermenter instead of a glass/plastic carboy (and this is coming from a guy with 3 glass vessels)...

1. Flatness of the bottom vs. convex carboy
2. Size of the magnet required (you're not going to fit anything bigger than 1" square into a glass neck).
3. Closer proximity to the stir plate itself.

How stupid would it be to have something that just agitates the whole fermenter like one of those coin operated beds you always see in the movies? Maybe time for a DIY baseplate connected to the top of a power sander hooked up to an electric timer so it's not wiggling all day long?
I'm not particularly adept at hydrodynamics, feel free to call me stupid. In fact, let me do it...that's stupid.

I'll probably just stick with shaking the damn thing every time I walk past it, but it's fun to think about this stuff.

I like where your head is at, but the constant friction of the stir bar could make for some nasty scratches on the bottom of the bucket, which in turn gives bugs a nice little cave to hide in. I know both surfaces are smooth, but it really doesn't seem to take much to scratch a bucket.

Still, maybe there is a solution? Like have a small, separate layer of plastic that you lay down for the stir bar to rest on?
 
So as I see it, that's 3 solid reasons to try a bucket fermenter instead of a glass/plastic carboy (and this is coming from a guy with 3 glass vessels)...

1. Flatness of the bottom vs. convex carboy
2. Size of the magnet required (you're not going to fit anything bigger than 1" square into a glass neck).
3. Closer proximity to the stir plate itself.

a-1. Not a problem with a well made stir plate. I frequently use a 1 gallon jug with a very convex bottom no problem.
a-2. This problem is very easy to avoid. Don't use the cross shaped stir bars. I use a 2-1/4" barbell type stir bar for my large starters and it works just fine.
a-3. This has not proved to be problem for me. Depending on the strength of the magnets used, closer proximity to the stir plate is not always desirable. I've been running with a gap of about 3/4", but I'm using some extremely strong magnets.

Your vibration suggestion is not all that crazy. I've often thought that a rocking mechanism would work well. It would be fairly easy to build a rocking platform and use a cheap, low rpm gearmotor to power it. I plan to build one before too long. I will post some pics if I ever get one operating.

FYI, I've been getting excellent results stepping up a 2 liter starter twice, then once more with 3.5+ liters in the gallon jug. I only make a starter this large when brewing 12 gallon batches of lager. The double step up seems to be sufficient for the 12 gallon ales. I say this as the beers have been consistently finishing out well and doing so at the low end of the suggested temperature ranges for a particular yeast. IMO, the yeast often gets blamed for low finishing gravities when the culprit is really mash temperature control. Not saying that the mash temperatures are always the problem, only that many times it's not a yeast issue. The trouble is, that points the finger directly at the brewer and this can be uncomfortable for some. :D
 
I don't think there is a problem with not stirring a large beer. Just pitch enough yeast, and possibly hit with O2 again 12h later. From your subject heading, I thought you would be discussing making starters in carboys, which I do sometimes. Higher gravity, 10G lager batches need big starters. I've never gotten a stir plate to work on carboys, apple juice jugs, or anything with a concave botom. At that point, I think you should use a stir arm that comes in from the neck. These systems are very expensive from lab supply sites, but the arms themselves are not so bad, so the rest would be good ole homebrewer creativity....
 
What i'm trying to do, is to specifically speed up fermentation times on certain beers. We have all waited close to a month for our favorite belgian to finish. If you don't let those bad boys finish, they will continue to ferment out in your nice 750ml bottles, and while they won't blow up, you will get an almost champagne like beer. As some of you know, it does not matter what you do to belgians, add O2, add sugar after fermentation, slosh around every day, bring up to higher temps. They take there own sweet time. This is a solution to that problem, or at least I'm hoping it will be. I'm doing a Saison next that I know takes at least 24 days to ferment out. What I will do is let it ferment for 3 days, then bring it up to 80 degrees, and throw it on the stir plate. I'm hoping to cut the fermentation time in half.
 
What i'm trying to do, is to specifically speed up fermentation times on certain beers. We have all waited close to a month for our favorite belgian to finish.

I'm doing a Saison next that I know takes at least 24 days to ferment out.

Wait, what?! A saison that takes over 3 weeks to finish primary fermentation!? There's something wrong elsewhere in the process there.
 
hexmonkey said:
Wait, what?! A saison that takes over 3 weeks to finish primary fermentation!? There's something wrong elsewhere in the process there.

Actually I have similar results as bruguru. I left a 1070 wort with wyeast belgian II in primary for 3 weeks, racked it, primed and bottled. FG was 1020 but it 'looked' like yeast was finished. I had old faithfull eruptions when I later opened those bottles. Brewing Clasic Styles also talks about this.
 
Actually I have similar results as bruguru. I left a 1070 wort with wyeast belgian II in primary for 3 weeks, racked it, primed and bottled. FG was 1020 but it 'looked' like yeast was finished. I had old faithfull eruptions when I later opened those bottles. Brewing Clasic Styles also talks about this.

Wyeast says 1762 yeast has Attenuation: 73-77%

1070 to 1020 = 71.5%, your attenuation
1070 to 1016 = 77.1%, the max attenuation for that strain according to Wyeast
1070 to 1018 = 74.3%, the attenuation expected by JZ in BCS (below)

Brewing Classic Styles says that you should expect that some saison yeasts will only attenuate around 75% and (especially with extract) to use simple sugars "to improve fermentability, up to 20% of the total sugars".

But he says to "add another yeast, such as dry champagne yeast, to get the beer to attenuate a little more." He doesn't say "it will attenuate more if there were some way of agitation".

His point in the book is that's all some saison yeast will do; just use another yeast to finish it up. Also note his reasoning is not "because it will turn into a bottle bomb", but because it won't be a dry enough finish.

megalomani - these are things I would look at if I had bottles of beer that gushed.
  • How did you measure your priming sugar?
  • Did you use a calculator to factor in the temperature of the beer?
  • Did you measure the FG of the beer that gushed to see how low the gravity dropped?
  • Could there have been contamination - were there off flavors in the gusher beer?

Other process-related questions to ask if you can't get the FG low enough:
  • AG: What temperature are you mashing at?
  • Extract: How fresh is the extract and/or where did it come from?
  • How much yeast are you pitching?
  • What temperature are you pitching at? Are you pitching cool and letting it warm up :))), or pitching warm and cooling it down :)()?
 
It's a 6.5 gallon carboy. I used a 12v 1a dc fan and a 50 lb rated 2 inch bar magnet. Rather than a rheostat, I opted for a LM317 based voltage regulator.

It is kind of a pain to get the thing balanced on the center but I don't have many issues with throwing. It usually takes me a few tries to get the thing spun up.

image-969746229.jpg
 
Wait, what?! A saison that takes over 3 weeks to finish primary fermentation!? There's something wrong elsewhere in the process there.

Nothing wrong with the process, this is how long it takes, and that's not including letting it age a month or so. This is with a gallon starter, it takes a while is all. And it's not that the beer is undrinkable, or a gusher, the increase in carbonation is slight. after about 6-9 months it's perfect, but like a champagne with the carbonation.
I've made quite a few belgians, and just trying to find a better way. Unfortunately, I havn't gotten around to try this experiment, as my brewing is in full swing for parties for the summer. Hopefully I be able to get around to it soon.
 
It's a 6.5 gallon carboy. I used a 12v 1a dc fan and a 50 lb rated 2 inch bar magnet. Rather than a rheostat, I opted for a LM317 based voltage regulator.

It is kind of a pain to get the thing balanced on the center but I don't have many issues with throwing. It usually takes me a few tries to get the thing spun up.

I had a vortex like that in my boil kettle test run. I am pumped since I ferment in Sankes and they have that nice flat bottom right under the dip tube. Of course you would have to trim the tube to get a stir bar under it, but the kettle worked with a tiny little stir bar and computer fan and magnet.
 
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