Australian Stirplates - Need Testers

[megabyte]

What would be good would be a timer of some sort ,So it only comes on every hr

Interesting idea bjay. Could you provide more info on why you'd want it running intermittently?
Is it Just so it stresses the yeast less?
It would be fun to implement a feature like that.

Would anyone else like this feature?

 

[bjay]

Dont know about stressing the yeast ,,,
I just dont think it needs to run all the time,But thats just me
When i have made starters before i just give it a wirl everytime i walk past and this seems to work no problems
Could be just over complicating things for the sake of it
I have played around programming pics in assembly language and this timer would be a nice project if i had the time,Although there would be a simple way around this timer without micro
The plate is still spinning nicely hardly any noise at all,Iam sure it will wizz up a nice starter

bjay

 

[The Scientist]

No need to worry about only running the stirbar intermitintly, you want to grow your starters up quickly as possible. So a constaint stir is what you need to do this.

See below comparisons:


Cheers,

TS

 

[Online Brewing Supplies]

No need to worry about only running the stirbar intermitintly, you want to grow your starters up quickly as possible. So a constaint stir is what you need to do this.

See below comparisons:
View attachment 39627

Cheers,

TS

Got to agree constant stir is the way to go.
GB

 

[bjay]

Not sure on run and rest or run constant will have to test it out myself,,
But all is good so far will make up a starter next week,,,
Its been running alll day and night no probs

bjay

 

[bcp]

That's interesting. It sounds more like 'shaken' in your experiment only means shaken at the beginning of the starter? If so, then it doesn't really address bjay's proposition, that regular circulation rather than constant circulation may be all that is required.

Who did that experiment?
Because this experiment didn't show the same results at all.

http://seanterrill.com/2010/01/14/aeration...yeast-starters/



Agitated = stir plate
Aerated = aquarium pump

"Conclusions

1. All other things being equal, a starter covered in foil will grow more yeast than one with an airlock.
2. The primary reason to use a stirplate is not the mechanical mixing of the starter, but the introduction of oxygen. Using an airlock significantly reduces the effectiveness of a stirplate.
3. Contrary to what other sources indicate, a stirplate does not produce several times as much yeast per unit volume.
4. Given that it can also be used to aerate the main batch of wort, an aquarium pump is probably a more cost-effective investment for a homebrewer than a stirplate."

Interesting piece about the use of foil. There is an interesting discussion at the end about his methodology and therefore whether or not his conclusions are watertight.

 

[bjay]

bcp

From what i can gather the airlock prevents the easy escape of co2 compared with foil
and that slows down the growth of yeast,, I am having success just shakin it every time i walk past so can only get better :chug:

cheers
bjay

 

[The Scientist]

That's interesting. It sounds more like 'shaken' in your experiment only means shaken at the beginning of the starter? If so, then it doesn't really address bjay's proposition, that regular circulation rather than constant circulation may be all that is required.

Who did that experiment?

Found it at Maltose Falcons:

http://www.maltosefalcons.com/tech/yeast-p...s-and-practices

Let me know what you think.

Cheers,

TS

 

[MeLoveBeer]

Found it at Maltose Falcons: http://www.maltosefalcons.com/tech/yeast-p...s-and-practices

Great read... of most interest was a statement contained in the recommendations (below), stating that a pellet or two of hops should be added to starters. Thought it stopped (or slowed) yeast growth.

Starter recommendations

Always make one. It will undoubtedly improve the quality of your beer.

Volume - 1-2 liters (quarts) minimum.

Composition - 1.035 -1.045 gravity (1/4 lb or 1 cup DME in 1 quart) plus amino acid/vitamin-based yeast nutrients (1/4 tsp/quart) and hops (a pellet or 2).

Preparation - Boiling for 15-30 minutes is sufficient for sanitization. Add hot to sanitized jar then cool. Don't worry about hot breaks. A starter prepared this way should be used within 1-2 days since it is not absolutely sterile.

Initiation- 10 ml mini-starter from yeast stock (superstarter). These should be grown for 1-3 days; the mini-starter should be cloudy with lots of yeast.

Treatment - Shake! Shake! Shake! This will give you 3 times more yeast.

Temperature -Room temperature (~ 75 F; ales can go up to 80 F).

Time - Usually 2-3 days after starting with either a 10 ml culture or a Wyeast packet. It only takes 1-2 days if using a 10-fold step up.

Storage - If for some reason you couldn't use your starter, put it in the refrigerator and keep as cold as possible. A day (or at least the morning) before you want to use it, pour off the liquid and replace it with some fresh starter (1/4 the original volume of the starter is more than enough) that has been boiled and cooled. It should be ready to pitch within 4-24 hours.

 

[The Scientist]

Great read... of most interest was a statement contained in the recommendations (below), stating that a pellet or two of hops should be added to starters. Thought it stopped (or slowed) yeast growth.

Yeah I wouldn't add any hops, as you said they add nothing to the yeast and more than likely Inhibit growth. If anything I'd acctually add a very small amount of yeast nutrient to the starter.

One of the most importaint things IMO is having a good SG for the yeast to start with. 1.040 is what you want to start with and you can raise this with each step up you do for your starter. For example, if your intended beer is going to have an SG of 1.080 you want to slowly bring your starter SG close to this mark as to not shock the yeast when you finnally add it to the wort.

Any comments from the floor?

 

[megabyte]

Hi Guys,

Feedback from the test stirplates has been VERY helpful so I'd like to give a big thanks to everyone that participated in testing and provided feedback.

Although this thread has been relatively quiet, I did receive a few PMs from testers who were too polite or shy to mention their issues publically. Aside from melovebeer's stirplate which arrived with its fan unstuck (sorry mate), BCP's stirplate threw a magnet, bjay's power supply gave up (replaced), and an honourable mention goes out to murdoch - despite his valliant efforts we had no luck stirring his domed bottom demijohns.

Almost all of these issues have been addressed for the first production batch of stirplates, however it looks like stirring vessels with moderately domed bottoms are never going to work effectively. Still, vessels with a mildly domed bottom like the 2 liter erlenmeyer flasks you can buy from sera at www.seratech.net (with free shipping - check them out) work great.

On another note...
I've set up an online store (www.digitalhomebrew.com) to sell the new stirplates. Being a software developer by day it was quite fun to build a website specifically to showcase them. It should also make it far easier for me to link payments and manage orders. I have posted an announcement in the retail thread here: http://www.aussiehomebrewer.com/forum//ind...showtopic=47379 so please feel free to ckeck it out and offer any feedback.

Cheers guys, It's been a blast!
-Michael Burton.

 

[kevin_smevin]

That's interesting. It sounds more like 'shaken' in your experiment only means shaken at the beginning of the starter? If so, then it doesn't really address bjay's proposition, that regular circulation rather than constant circulation may be all that is required.

Who did that experiment?
Because this experiment didn't show the same results at all.

http://seanterrill.com/2010/01/14/aeration...yeast-starters/



Agitated = stir plate
Aerated = aquarium pump

"Conclusions

1. All other things being equal, a starter covered in foil will grow more yeast than one with an airlock.
2. The primary reason to use a stirplate is not the mechanical mixing of the starter, but the introduction of oxygen. Using an airlock significantly reduces the effectiveness of a stirplate.
3. Contrary to what other sources indicate, a stirplate does not produce several times as much yeast per unit volume.
4. Given that it can also be used to aerate the main batch of wort, an aquarium pump is probably a more cost-effective investment for a homebrewer than a stirplate."

Interesting piece about the use of foil. There is an interesting discussion at the end about his methodology and therefore whether or not his conclusions are watertight.

This might seem picky, but i'd imagine there would be no statistical significance between those results. I dont think you could confidently say one is better then the other.

 

[Florian]

I have taken a few photos yesterday just to show how well the stir plate is able to stir even big starters. When looking at the pictures please consider that this is a huge 5L Erlenmeyer flask, so you obviously can't expect a massive vortex like the ones you get in a 1L or even 2L flask. But I think the point is that the starter is constantly on the move.
Against my expectations, the flask itself sits also nicely on the stir plate, it seems very stable and I wouldn't worry leaving the whole thing unattended. But if you're not comfortable, just place a few thick books or whatever you have on hand around the plate to give the flask more stability.

2500ml



2500ml with airation bubbles splitting from the vortex



3300ml



3300 ml close-up



4500ml



I have so far only tried this with the bigger stir bar, not the smaller one. I wonder if an even larger stir bar would make a difference at all.

Florian

 

[megabyte]

Thanks for posting those pics florian, that looks like a good vortex to me.
Don't discount the 25mm stirbar on its size alone. I've used the 25mm bars on my 2L flask and I found they tend to make a longer (deeper) thinner vortex and they are more stable when ramping up the speed. I don't know if that's any better theough.
I'd be interested to trial some larger bars, but it may require a different spacing on the magnets.

 

[sink cut]

Thanks for posting those pics florian, that looks like a good vortex to me.
Don't discount the 25mm stirbar on its size alone. I've used the 25mm bars on my 2L flask and I found they tend to make a longer (deeper) thinner vortex and they are more stable when ramping up the speed. I don't know if that's any better theough.
I'd be interested to trial some larger bars, but it may require a different spacing on the magnets.

Has anyone tried larger stir bars yet?

I brew 55L at once and want enough yeast out of my 5L flask. With the supplied stir bar I can only get a very small vortex going, not sure if I should find some bigger bars or if they would even work.

 

[megabyte]

Has anyone tried larger stir bars yet?

I brew 55L at once and want enough yeast out of my 5L flask. With the supplied stir bar I can only get a very small vortex going, not sure if I should find some bigger bars or if they would even work.

Hey Sink cut,
I've found that the spacing between the magnets inside the stirplate makes a huge difference on the stability of the stirbar. The stirplates I have built use a magnet spacing of around 30mm which I have found to be a good compromise for both 25mm and 40mm stirbars.

If you want to try a larger stirbar you may need to alter the stirplate by spacing the internal magnets further apart. Unfortunately, it probably won't work as well with your 25mm stirbar after the mod.

Keep us posted if you decide to experiment.
Cheers,
Mick.

 

[Hogan]

Has anyone tried larger stir bars yet?

I brew 55L at once and want enough yeast out of my 5L flask. With the supplied stir bar I can only get a very small vortex going, not sure if I should find some bigger bars or if they would even work.

I use a 25mm flat (tubeular) bar in my 1lt erlenmeyer and a 55mm in the 2lt. I bought a 5lt vessel that had a slightly domed bottom and the flat bar took a hell of a lot of trouble to stay centered as it was pivoting on only a very small area of the bar. I got on to Bacto Scientific at Liverpool and purchased a 55mm dumbell or barbell (looks like it sounds) and that was successful because it had two points of contact, one on either side of the dome. I did have to add a couple more RE magnets to my stirplate as the glass bottom was thicker than the erlenmeyer. This could result in the small bars being hard to rotate as the magnetic pull has increased but this can be sorted by putting a couple of spacers between the plate and the flask.


Cheers, Hoges.

 

[MeLoveBeer]

Hey Sink cut,
I've found that the spacing between the magnets inside the stirplate makes a huge difference on the stability of the stirbar. The stirplates I have built use a magnet spacing of around 30mm which I have found to be a good compromise for both 25mm and 40mm stirbars.

If you want to try a larger stirbar you may need to alter the stirplate by spacing the internal magnets further apart. Unfortunately, it probably won't work as well with your 25mm stirbar after the mod.

Keep us posted if you decide to experiment.
Cheers,
Mick.

I've been using a 40mm bar with my 3L starters quite successfully (just need to experiment a bit with speed, because it takes a bit to move them and once you ramp it up too much they tend to spin off axis quickly). I now just leave the dial on the same setting and am able to walk away for a couple of days without drama's.

 

[Siborg]

Hey Michael. When are you building some more of these? I'm looking at getting one.

 

[megabyte]

Hey Michael. When are you building some more of these? I'm looking at getting one.

Hi Siborg, I got held up with sourcing some parts, but I should have more in the store next week.
Cheers,
Mick.