stirplate getting warm?
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I wouldn't worry too much but I would check the temp of the starter just to be certain.
flars
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I had the same problem with a discarded lab stir plate. After 12 or so hours the starter was at 78°. I aimed a small fan at it which cooled the starter to room temperature.
I'm still using the same stir plate, but instead of making my starter in glass I'm using plastic. The plastic does not tramsmit heat as effectively. No need for the fan anymore.
I'm still using the same stir plate, but instead of making my starter in glass I'm using plastic. The plastic does not tramsmit heat as effectively. No need for the fan anymore.
yeah, it's normal for those stirplates to get a little warm with continued use.
Do make sure that if it is a combo hot/stir plate that the hot plate is turned off
I had a new tech in my lab make that mistake once and it ended very poorly for a plastic cup.
Do make sure that if it is a combo hot/stir plate that the hot plate is turned off
I had a new tech in my lab make that mistake once and it ended very poorly for a plastic cup.
zachattack
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From Jamil's website:
Q: Does a starter need to be kept at the same temperature as it is going to ferment the batch of beer later?
No, but there are practical limits to how high or low you can go.
Warmer starters (up to 98°F, 37°C) equal more rapid yeast growth, but using these very high propagation temperatures negatively affects the viability and stability of the resulting yeast. Very rapid growth or excessive growth can result in weaker cell membranes due to lower unsaturated fatty acid concentrations. Lager yeasts tend to be especially sensitive to high temperatures.
The cooler you ferment the starter (down to the planned fermentation temperature for the main batch) the slower the yeast growth, but the yeast can be healthier than yeast coming from a high temperature starter.
Keep starters between 65°F (18°C) and 75°F (24°C). A temperature around the low 70s (72°F, 22°C) strikes the best balance for the propagation of yeasts. Lager yeast starters can be kept a few degrees cooler and ale yeasts can be kept a few degrees warmer, but this temperature strikes a good balance of yeast health and efficient propagation for both types of yeast.
If you are going to pitch the starter at high krauesen, it is best to keep the starter within 5 degrees Fahrenheit (3°C) of the wort temperature of the main batch. Pitching a very warm, active starter into cold wort can stun the yeasts and with lager yeasts this can cause a higher incidence of petite mutants, which can negatively affect attenuation, flocculation, and increase hydrogen sulfide production.
You can add small amounts of cool wort to the starter over time, to bring the temperature down gradually, but it is really better to keep everything closer to fermentation temperatures from the beginning. Any time yeast sense a big drop in temperature, they slow down and drop out.
Q: Does a starter need to be kept at the same temperature as it is going to ferment the batch of beer later?
No, but there are practical limits to how high or low you can go.
Warmer starters (up to 98°F, 37°C) equal more rapid yeast growth, but using these very high propagation temperatures negatively affects the viability and stability of the resulting yeast. Very rapid growth or excessive growth can result in weaker cell membranes due to lower unsaturated fatty acid concentrations. Lager yeasts tend to be especially sensitive to high temperatures.
The cooler you ferment the starter (down to the planned fermentation temperature for the main batch) the slower the yeast growth, but the yeast can be healthier than yeast coming from a high temperature starter.
Keep starters between 65°F (18°C) and 75°F (24°C). A temperature around the low 70s (72°F, 22°C) strikes the best balance for the propagation of yeasts. Lager yeast starters can be kept a few degrees cooler and ale yeasts can be kept a few degrees warmer, but this temperature strikes a good balance of yeast health and efficient propagation for both types of yeast.
If you are going to pitch the starter at high krauesen, it is best to keep the starter within 5 degrees Fahrenheit (3°C) of the wort temperature of the main batch. Pitching a very warm, active starter into cold wort can stun the yeasts and with lager yeasts this can cause a higher incidence of petite mutants, which can negatively affect attenuation, flocculation, and increase hydrogen sulfide production.
You can add small amounts of cool wort to the starter over time, to bring the temperature down gradually, but it is really better to keep everything closer to fermentation temperatures from the beginning. Any time yeast sense a big drop in temperature, they slow down and drop out.
So I have the same "problem." I put a folded in half kitchen towel under the flask and it seems to pretty efficiently distribute the heat out of the starter. I have had it get up in to the mid-low 80s before with no noticeable off flavors. Those lab stirrers are much sturdier than your typical computer case fan, DIY ones.
snowblind5150
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You could create a support for a glass plate to sit about 1/8" above the stirplate. That should still allow for the stir bar to work, but would prevent heat transmission from the plate to the flask.
simple adhesive rubber feet would do for a support for the flask and create a stable place for the flask
horseinmay
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I also have an old lab stir plate and the same problem. I'm thinking about removing the guts of it and installing a computer fan, while reusing the case and controls. Mine does not have a heating function, but it gets much hotter than I'm comfortable with (90's?)
fixitoscar
Well-Known Member
I picked up an old lab stir plate on ebay for cheap. This is what I do. Looked around the garage and found some small diameter rubber hose and laid 2 pcs on the stir plate to support my flask and make a gap in between the 2.. If i'm doing a lager starter i'll use a small fan to blow across the gap in between the stir plate and flask.
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<--- this is what I'd try...or a small piece of something not thermally conductive: rubber, plastic, foam, etc. Modify with fan would be after the easy/inexpensive options fail!
I have one that does this too. My starters were getting up near 90F. I used a silicon pot holder between the flask and the stirplate. It still got warm, but it kept it around 75F-80F.
I ended up replacing it with a used Corning PC350 model off of ebay. Now I have 2 of them, and they run nice and cool. If you can get your hands on one of these I highly recommend it. They are awesome.
I ended up replacing it with a used Corning PC350 model off of ebay. Now I have 2 of them, and they run nice and cool. If you can get your hands on one of these I highly recommend it. They are awesome.
GNBrews
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I had the same problem with an older Thermolyne-brand stirrer. The heat was being generated by the variable resistor that was used in the speed control circuit. Since the motor was just a A/C induction motor, I replaced the speed control with a dimmer switch. It's not the prettiest contraption, but it works much better than before. I would start with rubber feet spacers though, and see if that offers enough isolation.
Thats an F'ing great idea, I'm going to do that to my old lab stir plate I have the same problem with.
KampusBrewery
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I have the same issue, I usually put a plate on the stirrer and fill it with water before putting the flask on it.
