Double stir plate project

[f00b4r]

Came across a nice dual stir plate project on Github from one of the guys on the main German homebrew forum. They have actually created a custom PCB board for it that you can buy to build one.

[vacant]

Looks great. It's images like this that sometimes make me wish I wasn't a bodger.

For the moment, I'll stick to my built-from-scrap stir plate - phone charger connected by bent paper clips to a computer fan with a magnet from an old hard drive stuck on it. Tell a lie, I did spend £4.16 on a Zalman fanmate 2 speed controller as the computer fan is fixed speed!

[guypettigrew]

Very pretty. But why would you need a double stir plate?

Guy

[LeeH]

Spitting a batch to showcase yeasts.


Sent from my iPhone using Tapatalk Pro

[f00b4r]

Double brew day or even building up two smaller starters to combine if you do not have bigger flasks.

[guypettigrew]

Obvious when you know! Thanks.

Guy

[WalesAles]

Very pretty. But why would you need a double stir plate?

Guy

Flippin` `eck Guy!
It just looks Bloody Lovely Mun!
Every Kit Brewer should strive to own one of these. Even if it is never used, I can open my Brewshed
to my brother and say `Look what I`ve got`.
And He will say `Don`t you ever stop buying stuff you will never use`.
They just don`t get it, do they!

WA

Sent from my Big Sofa.

[Cobnut]

very pretty.

Not sure I need a double stir plate, though.

One issue I do have is with my 2L flask - it seems to have a base which isn't flat and unless I am super-careful, the magenetic stirrer spins off the centre of the base and lands (not stirring) at the side. Maybe I bought a flask which is too cheap?

Anyone else have similar issues? Would a different sized (longer/shorter) stirrer help?

Perplexed of Suffolk.

[guypettigrew]

Same problem here! I centre the stir bar onto the magnet in the top plate and then turn the speed of the stirrer up very, very slowly. It still whizzes off sometimes!

Guy

[brewpete]

That's amazing looks like part of a high end HiFi system

[Kev888]

One issue I do have is with my 2L flask - it seems to have a base which isn't flat and unless I am super-careful, the magenetic stirrer spins off the centre of the base and lands (not stirring) at the side. Maybe I bought a flask which is too cheap?

Anyone else have similar issues? Would a different sized (longer/shorter) stirrer help?

Same problem here! I centre the stir bar onto the magnet in the top plate and then turn the speed of the stirrer up very, very slowly. It still whizzes off sometimes!

I find the triangular section stir-bars are more stable than the ring or oval type, and so can cope better with slightly domed bases. Similarly, small-ish ones (say an inch or less) are more stable than longer ones. Though either way the stir-plate's magnet arrangement (e.g. spacing) needs to be suitable for whatever length of bar is chosen; mismatching plate design and bar length is another common cause of instability.

Also there are lots of videos on the net showing off rapid whirlpool-like capability, which might lead people into thinking this is wanted (and then they worry about shear stress!). But fairly slow and steady stirring is all that is needed, just to promote oxygen exchange with the head space - with perhaps no more than a small dimple forming at the centre of the swirl.

Unfortunately the computer-type fans people tend to use (for the quiet brushless motors) don't have an ideal speed range, so can be quite tricky to control subtly at the slow speeds wanted; maybe the system in the OP would help there. Not only do we want 'very' slow speed (compared to the fan's normal range), but it really helps to build up to this slowly, so the bar is never trying to get too far ahead of the wort.

[richard080561]

Looks great. It's images like this that sometimes make me wish I wasn't a bodger.

For the moment, I'll stick to my built-from-scrap stir plate - phone charger connected by bent paper clips to a computer fan with a magnet from an old hard drive stuck on it. Tell a lie, I did spend £4.16 on a Zalman fanmate 2 speed controller as the computer fan is fixed speed!

It sounds like you used the same design as me.