Galena
Landlord.
Any recommendations for a decent budget stir plate, I don't want to build one so looking for something that will happily stir up to 3000mls wort I suppose.
Stir plate
- Thread starter Galena
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Galena
Landlord.
Thanks, was the supplied rod okay or did you buy something different?
Galena
Landlord.
Thanks. I'll get one ordered then
Galena
Landlord.
Yes, no complaints, I have made starters up to 2.5 litres and though my 3 litre Erlenmeyer flask is wider than the base of the stirrer it sits on just fine.
Good call. I've got a big bag of rare earth magnets and there should be something in there that'll do the job, but it's not something I'd have thought of initially. Stirrer, flasks, and stir bars have just been ordered - looking forward to making my first starter now.
I've been known to pour the stir bar in to the fermenter. I've just left it there until I rack the beer off. it hasn't hurt the beer or the stir bar
Galena
Landlord.
True, but it would disrupt my next starter
May be stir bars should be like hydrometers with a rule that says you should always have a spare.True, but it would disrupt my next starter
Galena
Landlord.
Or a magnet
timtoos
Regular.
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I have a few. I imported one from the US a few years back and I never rated it. It had a pot to control the speed but the magnet stuck onto the fan (yes when opened up and it was pretty homemade rubbish) wasnt strong and it kept losing the stirrer bar which was a pain.
I got fed up with it so when I was on beerhawk (when they sold HB gear) I saw they had the Maelstrom stirrers on deal so purchased one, Its brilliant, has loads of functions like timer etc which I guess you dont really need tbh. I have made 3L + starters on it no issues. I guess you could do 5L starter on this kit of kit.
I got fed up with it so when I was on beerhawk (when they sold HB gear) I saw they had the Maelstrom stirrers on deal so purchased one, Its brilliant, has loads of functions like timer etc which I guess you dont really need tbh. I have made 3L + starters on it no issues. I guess you could do 5L starter on this kit of kit.
I'm on my second stir plate. The first was a bought one that, while working fine, appeared to be based on a 12V computer fan like most are. The problem with these is that they are high speed low torque motors that tend to get bogged down when the starter gets thick with yeast and easily throw the stir bar due to small disc magnets.
The one I use now is self built based on a cheap high-torque low speed 12V geared motor off ebay connected through a PWM controller module. I fixed a small strip of steel bar to the motor shaft and added two very fat neodymium magnets to the ends. These pull hard on the stir bar so I can use a large 5cm bar that never gets thrown and the high-torque, geared motor means that the speed is maintained throughout. It's one of those motors that when you switch it off the shaft stops dead instantly with zero inertia. All in must have been £10 worth of components and it easily handles starters in 5 litre flask.
The one I use now is self built based on a cheap high-torque low speed 12V geared motor off ebay connected through a PWM controller module. I fixed a small strip of steel bar to the motor shaft and added two very fat neodymium magnets to the ends. These pull hard on the stir bar so I can use a large 5cm bar that never gets thrown and the high-torque, geared motor means that the speed is maintained throughout. It's one of those motors that when you switch it off the shaft stops dead instantly with zero inertia. All in must have been £10 worth of components and it easily handles starters in 5 litre flask.
I have a home made stir plate which works fine. Very similar to description of diy version described above. However I'm intrigued by the 'shaken not stirred' method (Shaken, not Stirred: The Stir Plate Myth Buster | Experimental Homebrewing) and have bought a large jar to try this out next time I make a starter. Worth a read, the author has made an in depth study of yeast and backs his arguments up convincingly IMHO. I think the argument can be summed up as stir plates using an Erlenmeyer flask don't oxygenate the starter efficiently and the rod & vortex physically stress the yeast cells too much.
Sadly as far as I'm aware no one has done a lab based study to definitively bust or support this particular myth.
Sadly as far as I'm aware no one has done a lab based study to definitively bust or support this particular myth.
Experiments have been done that show increased stir-rate results in higher growth. Search down for "stir speed". There's loads of other great experimental data on Kai's page including one on the starter's access to air.
ok, lots of good stuff there but on a quick scan through it's not a comparison of the shake method vs a stir plate, if it's there I missed it.
Yes you're right that comparison is not there. There is good data to show the benefit of access to air during fermentation though.
Yes, true, but the 'shake not stirred' method aims to provide a lot more dissolved oxygen just prior to yeast pitch and then avoids the physical stress on the yeast caused by the stir rod & vortex. Having not yet tried it I can't shout its praises but the potential is that a decent sized large mouth glass jar is better than an expensive stir plate & conical flask. All I'm saying really is that it's worth considering before thinking (as I did) that a stir plate is essential & perhaps rushing out and spending a lot of money on one. I built mine from scrap + geared motor off eBay like you did I think, so it owes me nothing and I quite enjoy experimenting so I plan to give the shake not stirred method a go.
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