Fermenting starts warm, and I do mean warm

Fermenting starts warm, and I do mean warm

Post by Scott Lon » Sun, 28 Aug 2005 01:09:46



First, the background. I recently picked up a used stir plate, and it
clearly has some circuitry issues. It has a speed control which doesn't
work above the "5" setting (speed flies out of control after that), and
it isn't supposed to be a hot plate, but boy, does it heat up.

The first time I used it I almost burned my house down. And that was
when I thought I had it turned OFF. Now, when I turn it off I also
unplug it, lest it burst into flame. When it's actually running, the
spinning rotor inside seems to move the air around enough to keep it
below, oh I don't know, 120 F or so.

The first starter I tried to make was destroyed, by cooking on the stir
plate after I thought I'd turned it off. Now I'm making another one,
and it seems to have survived its ordeal except that it fermented warm,
and by warm I mean like around 100 degrees. Not far beyond body
temperature, but definitely in that range.

Is this starter going to be usable, or will it turn my beer into a
hellish goo? Obviously, I'll decant as much of the starter beer off the
yeast as I can, before I pitch it.

Scott

 
 
 

Fermenting starts warm, and I do mean warm

Post by The Artist Formerly Known as Kap'n Salt » Sun, 28 Aug 2005 01:48:32


Quote:

> First, the background. I recently picked up a used stir plate, and it
> clearly has some circuitry issues. It has a speed control which doesn't
> work above the "5" setting (speed flies out of control after that), and
> it isn't supposed to be a hot plate, but boy, does it heat up.

> The first time I used it I almost burned my house down. And that was
> when I thought I had it turned OFF. Now, when I turn it off I also
> unplug it, lest it burst into flame. When it's actually running, the
> spinning rotor inside seems to move the air around enough to keep it
> below, oh I don't know, 120 F or so.

> The first starter I tried to make was destroyed, by cooking on the stir
> plate after I thought I'd turned it off. Now I'm making another one,
> and it seems to have survived its ordeal except that it fermented warm,
> and by warm I mean like around 100 degrees. Not far beyond body
> temperature, but definitely in that range.

> Is this starter going to be usable, or will it turn my beer into a
> hellish goo? Obviously, I'll decant as much of the starter beer off the
> yeast as I can, before I pitch it.

Provided you didn't kill the yeast, warmer is actually better. I can't remember
the upper temp limit for saccharomyces, though, before high temps become
detrimental. Note that you should generally pour off most of the starter beer
when you use a stir plate.

I know some stir plates tend to run warm, but yours may also be a hot plate. Is
it? If so, you may be able to disconnect the heading element inside. You could
also try to come up with some sort of insulator to put between the stir plate
amd the flask, but it needs to be thin, or you won't get enough magnetic "grab"
to keep the bar spinning properly.  Don't have any suggestions offhand for a
suitable material, but others here may have some ideas.

Hope that helps -- m

--
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Fermenting starts warm, and I do mean warm

Post by John 'Shaggy' Kolesa » Sun, 28 Aug 2005 01:57:42



Quote:
> First, the background. I recently picked up a used stir plate, and it
> clearly has some circuitry issues. It has a speed control which doesn't
> work above the "5" setting (speed flies out of control after that), and
> it isn't supposed to be a hot plate, but boy, does it heat up.

> The first time I used it I almost burned my house down. And that was
> when I thought I had it turned OFF. Now, when I turn it off I also
> unplug it, lest it burst into flame. When it's actually running, the
> spinning rotor inside seems to move the air around enough to keep it
> below, oh I don't know, 120 F or so.

> The first starter I tried to make was destroyed, by cooking on the stir
> plate after I thought I'd turned it off. Now I'm making another one,
> and it seems to have survived its ordeal except that it fermented warm,
> and by warm I mean like around 100 degrees. Not far beyond body
> temperature, but definitely in that range.

> Is this starter going to be usable, or will it turn my beer into a
> hellish goo? Obviously, I'll decant as much of the starter beer off the
> yeast as I can, before I pitch it.

I'd be worried about killing the yeast.  IMO, it sounds like you need to
get a different kind of stir plate.  You don't want one with a heating
element in it as well.  Mine doesn't get anywhere near that warm when
running.

John.

 
 
 

Fermenting starts warm, and I do mean warm

Post by Jono » Sun, 28 Aug 2005 02:21:28


Quote:

> First, the background. I recently picked up a used stir plate, and it
> clearly has some circuitry issues. It has a speed control which doesn't
> work above the "5" setting (speed flies out of control after that), and
> it isn't supposed to be a hot plate, but boy, does it heat up.

> The first time I used it I almost burned my house down. And that was
> when I thought I had it turned OFF. Now, when I turn it off I also
> unplug it, lest it burst into flame. When it's actually running, the
> spinning rotor inside seems to move the air around enough to keep it
> below, oh I don't know, 120 F or so.

> The first starter I tried to make was destroyed, by cooking on the stir
> plate after I thought I'd turned it off. Now I'm making another one,
> and it seems to have survived its ordeal except that it fermented warm,
> and by warm I mean like around 100 degrees. Not far beyond body
> temperature, but definitely in that range.

> Is this starter going to be usable, or will it turn my beer into a
> hellish goo? Obviously, I'll decant as much of the starter beer off the
> yeast as I can, before I pitch it.

> Scott

Hey Scott, what is the brand/model # of the plate?
 
 
 

Fermenting starts warm, and I do mean warm

Post by Scott Lon » Sun, 28 Aug 2005 02:38:09



Quote:
> I know some stir plates tend to run warm, but yours may also be a hot
> plate. Is it? If so, you may be able to disconnect the heading element
> inside.

It isn't supposed to be a hot plate. The heat mostly comes from the
area near the speed control dial, not the top of the plate. There is
very clearly something wrong with the unit.

Also, when I turn the dial past 5 (it ranges from 1 to 10), the thing
flies out of control. And I don't just mean that the stir bar breaks
away and jumps around -- I mean the motor revs up and sounds like a jet
engine. It's like turning the dial anywhere past 5 just ramps it
straight up to maximum power.

So I am very suspicious that a rheostat or other component near the
speed control is failing.

Quote:
> You could also try to come up with some sort of insulator to put between
> the stir plate amd the flask, but it needs to be thin, or you won't get
> enough magnetic "grab"

That's exactly what I did. I used a thin-profile plastic CD case.
Seemed to work okay.

Scott

 
 
 

Fermenting starts warm, and I do mean warm

Post by Scott Lon » Sun, 28 Aug 2005 02:43:29


Quote:

> Hey Scott, what is the brand/model # of the plate?

It is a Precision Mag Mix, 8 inch diameter. Here's a picture of it:

http://images.channeladvisor.com/Sell/SSProfiles/30050944/Images/sm_3...

The area near the words "Mag Mix" is where the heat appears to be
coming from. Not the top of the plate. This is not intended to be a hot
plate.

When the unit is initially plugged in, nothing happens. But if you turn
the dial to start it, and then turn it back to stop it, it will begin
to heat up and continue to heat up, presumably until it catches fire.
The only way to stop it is to actually unplug it.

I'm currently running it, unsupervised, but it is inside a large
galvanized metal tub which should sufficiently contain it in the event
that something happens.

I may take it apart tonight just to see if there's anything OBVIOUSLY
wrong with it, that I might have parts to fix.

Ahh, the joys of Ebay.

Scott

 
 
 

Fermenting starts warm, and I do mean warm

Post by The Artist Formerly Known as Kap'n Salt » Sun, 28 Aug 2005 02:43:41


Quote:


>>I know some stir plates tend to run warm, but yours may also be a hot
>>plate. Is it? If so, you may be able to disconnect the heading element
>>inside.

> It isn't supposed to be a hot plate. The heat mostly comes from the
> area near the speed control dial, not the top of the plate. There is
> very clearly something wrong with the unit.

> Also, when I turn the dial past 5 (it ranges from 1 to 10), the thing
> flies out of control. And I don't just mean that the stir bar breaks
> away and jumps around -- I mean the motor revs up and sounds like a jet
> engine. It's like turning the dial anywhere past 5 just ramps it
> straight up to maximum power.

> So I am very suspicious that a rheostat or other component near the
> speed control is failing.

>>You could also try to come up with some sort of insulator to put between
>>the stir plate amd the flask, but it needs to be thin, or you won't get
>>enough magnetic "grab"

Honestly, based on your description I'd be concerned about the safety of running
this thing unattended. You might want to look into getting another plate --
which I know isn't what you want to hear, but it's better than starting a house
fire.

Cheers -- m
--
(Replies: cleanse my address of the Mark of the Beast!)

Teleoperate a roving mobile robot from the web:
http://www.swampgas.com/robotics/rover.html

Coauthor with Dennis Clark of "Building Robot Drive Trains".
Buy several copies today!

 
 
 

Fermenting starts warm, and I do mean warm

Post by Scott Lon » Sun, 28 Aug 2005 02:46:56


Quote:

> I'd be worried about killing the yeast.  IMO, it sounds like you need to
> get a different kind of stir plate.  You don't want one with a heating
> element in it as well.  Mine doesn't get anywhere near that warm when
> running.

Well, something inside the unit is acting like a heating element, but
it's not intended to! :-) I suspect that the heat problem and the speed
control problem are actually the same problem.

My main concern is whether yeast cultured at 100 degrees will have any
negative impacts on a beer. I don't believe the temperature got much
beyond that. Just to be safe, I'll pour a little boiled DME into the
flask tonight and see if it ferments that.

Scott

 
 
 

Fermenting starts warm, and I do mean warm

Post by Scott Lon » Sun, 28 Aug 2005 02:49:45



Quote:
> Honestly, based on your description I'd be concerned about the safety
> of running this thing unattended. You might want to look into getting
> another plate -- which I know isn't what you want to hear, but it's
> better than starting a house fire.

I'm sure you're right... After this run I'm going to stop using it
until I can figure out for certain what's wrong with it.

Scott

 
 
 

Fermenting starts warm, and I do mean warm

Post by Bob » Sun, 28 Aug 2005 02:49:59



Quote:

> > Hey Scott, what is the brand/model # of the plate?

> It is a Precision Mag Mix, 8 inch diameter. Here's a picture of it:

http://images.channeladvisor.com/Sell/SSProfiles/30050944/Images/sm_3...

Quote:

> The area near the words "Mag Mix" is where the heat appears to be
> coming from. Not the top of the plate. This is not intended to be a hot
> plate.

> When the unit is initially plugged in, nothing happens. But if you turn
> the dial to start it, and then turn it back to stop it, it will begin
> to heat up and continue to heat up, presumably until it catches fire.
> The only way to stop it is to actually unplug it.

> I'm currently running it, unsupervised, but it is inside a large
> galvanized metal tub which should sufficiently contain it in the event
> that something happens.

> I may take it apart tonight just to see if there's anything OBVIOUSLY
> wrong with it, that I might have parts to fix.

I suspect that the speed controller is failing. I would not recommend using
this unit until it is fixed to avoid burning your house down. Who knows what
the next failure mode will be?

Bob

 
 
 

Fermenting starts warm, and I do mean warm

Post by John 'Shaggy' Kolesa » Sun, 28 Aug 2005 03:14:26



Quote:
> When the unit is initially plugged in, nothing happens. But if you turn
> the dial to start it, and then turn it back to stop it, it will begin
> to heat up and continue to heat up, presumably until it catches fire.
> The only way to stop it is to actually unplug it.

You also mentioned that the speed control settings for the motor
don't work as expected.  I'm wondering if there is an electrical short
or something inside the motor, causing both the control problems as well
as the heat build up.  You may be burning up the motor.

That could be why they sold it in the first place.  ;)

John.

 
 
 

Fermenting starts warm, and I do mean warm

Post by John 'Shaggy' Kolesa » Sun, 28 Aug 2005 03:37:54



Quote:
> My main concern is whether yeast cultured at 100 degrees will have any
> negative impacts on a beer. I don't believe the temperature got much
> beyond that. Just to be safe, I'll pour a little boiled DME into the
> flask tonight and see if it ferments that.

I do know that when reading instructions for rehydrating dry yeast, they all
say to keep the water below 105F.  I'm not sure what temp will actually kill
yeast, but I suspect 100F is close.  I found one wine making website that
stated (don't know if it's true or not) yeast will only survive for a few
hours at 105F, and will die within minutes at 140F.

I suspect a starter kept at 100F for several days would probably not be
a very good idea.  At the least it would probably reduce the viability, if
it doesn't kill them all.

John.

 
 
 

Fermenting starts warm, and I do mean warm

Post by Jono » Sun, 28 Aug 2005 06:40:54


Quote:




>>>Hey Scott, what is the brand/model # of the plate?

>>It is a Precision Mag Mix, 8 inch diameter. Here's a picture of it:

> http://images.channeladvisor.com/Sell/SSProfiles/30050944/Images/sm_3...

>>The area near the words "Mag Mix" is where the heat appears to be
>>coming from. Not the top of the plate. This is not intended to be a hot
>>plate.

>>When the unit is initially plugged in, nothing happens. But if you turn
>>the dial to start it, and then turn it back to stop it, it will begin
>>to heat up and continue to heat up, presumably until it catches fire.
>>The only way to stop it is to actually unplug it.

>>I'm currently running it, unsupervised, but it is inside a large
>>galvanized metal tub which should sufficiently contain it in the event
>>that something happens.

>>I may take it apart tonight just to see if there's anything OBVIOUSLY
>>wrong with it, that I might have parts to fix.

> I suspect that the speed controller is failing. I would not recommend using
> this unit until it is fixed to avoid burning your house down. Who knows what
> the next failure mode will be?

> Bob

I'm just worried that since it not supposed to be a hot plate and you do
fix it, it may have damaged some other components that have been
affected by the heat and will fail again in the future.  I'd get a new
stirrer and rest easy that the house won't burn down, better safe than
sorry!
 
 
 

Fermenting starts warm, and I do mean warm

Post by PJ » Sun, 28 Aug 2005 06:45:50



Quote:
> Also, when I turn the dial past 5 (it ranges from 1 to 10), the thing
> flies out of control. And I don't just mean that the stir bar breaks
> away and jumps around -- I mean the motor revs up and sounds like a jet
> engine. It's like turning the dial anywhere past 5 just ramps it
> straight up to maximum power.

> So I am very suspicious that a rheostat or other component near the
> speed control is failing.

> Scott

I believe the rheostat has a broken connection about 1/2 way from the
beginning to the end of the 'winding'. The indication that you are
describing is that from the low setting to about mid-way - you are
getting 'some' control. This is an indication that you are getting
some reduction to motor voltage & current. As soon as you
turn the control past the "5" mark it takes off.. That is an indication
that the rheostat is open. Past "5"  the motor control is connected
to the high side without benefit of the drop across the rheostat.

Damn...  It is soooo hard to put into words.  Damn.. Damn...

Sigh..!!

PJ

 
 
 

Fermenting starts warm, and I do mean warm

Post by Scott » Sun, 28 Aug 2005 06:52:06


Quote:

> As soon as you turn the control past the "5" mark it takes off.. That is an
> indication that the rheostat is open. Past "5"  the motor control is
> connected to the high side without benefit of the drop across the rheostat.

> Damn...  It is soooo hard to put into words.  Damn.. Damn...

Actually I think you stated it pretty clearly. This is also what I
suspect is happening.

Another piece of evidence... I can actually turn it up to 6,
temporarily. After a period of time, anywhere from a few seconds to a
few minutes, it becomes unstable and once again flies off to full
speed.

I think the heat has something to do with it -- it's stable until it
heats up sufficiently, at which point some component bends/seperates
and shorts out the rheostat.

I guess it's time to play doctor on a piece of equipment.

Scott