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pcmax

Stir Plate

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I recently made a stir plate from an old cigar box and a PC fan (YouTube is such a great resource) it seemed to work well on my first starter which was for a WLP Cream Ale yeast. After pitching the 1 liter starter fermentation & vigorous airlock activity commenced after about 5hrs.

 

What i don't fully understand is the primary reason for spinning the starter round & round for 24-36hrs. Is it to keep the yeast in suspension so that they have a better shot at munching through the sweet wort or is it to allow aeration?

 

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I recently made a stir plate from an old cigar box and a PC fan (YouTube is such a great resource) it seemed to work well on my first starter which was for a WLP Cream Ale yeast. After pitching the 1 liter starter fermentation & vigorous airlock activity commenced after about 5hrs.

 

What i don't fully understand is the primary reason for spinning the starter round & round for 24-36hrs. Is it to keep the yeast in suspension so that they have a better shot at munching through the sweet wort or is it to allow aeration?

 

I had wondered the same - BYO reckons "A constantly-stirred yeast starter will yield a higher cell count than an unstirred starter."

http://byo.com/mead/item/398-build-your-own-stir-plate

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I recently made a stir plate from an old cigar box and a PC fan (YouTube is such a great resource) it seemed to work well on my first starter which was for a WLP Cream Ale yeast. After pitching the 1 liter starter fermentation & vigorous airlock activity commenced after about 5hrs.

 

Hi pcmax. Could you do me a favour and please let me know what you think of this yeast after it is ready? As you know WLP080 is an ale/lager blend' date=' as is the dry yeast that comes in the APA, and Mexican Cervesa kits. I would like to know how you think they compare? Of course you will be getting a higher cell count with your stir plate, which might complicate the comparison.

 

Whenever I use the Coopers ale/lager blend, which I like very much, I always select WLP080 in Ian's Spreadsheet, to hopefully get a more accurate attenuation estimate. Given recent discussion about yeast in some other threads, I am thinking of trying to first rehydrate the APA yeast and then make a starter with it, which I would have to do manually. I have never made a starter and don't have a stir plate. I am not as handy as you and would not dare tackle electrical wiring! [img']lol[/img]sad

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Hi pcmax. Could you do me a favour and please let me know what you think of this yeast after it is ready? As you know WLP080 is an ale/lager blend, as is the dry yeast that comes in the APA, and Mexican Cervesa kits. I would like to know how you think they compare? Of course you will be getting a higher cell count with your stir plate, which might complicate the comparison.

 

Whenever I use the Coopers ale/lager blend, which I like very much, I always select WLP080 in Ian's Spreadsheet, to hopefully get a more accurate attenuation estimate. Given recent discussion about yeast in some other threads, I am thinking of trying to first rehydrate the APA yeast and then make a starter with it, which I would have to do manually. I have never made a starter and don't have a stir plate. I am not as handy as you and would not dare tackle electrical wiring! lolsad

 

Hi Cristina,

I'm no expert and probably won't be able to pick the subtle differences of yeast types however my observations so far are that the yeast fired up almost immediately, airlock started bubbling about 5hrs after pitching, it formed a large (about 2") krausen after a couple of days. OG was 1.042 and yesterday after 5 days in the fermenter the krausen had all but disappeared with hardly any bubbles still rising. I took a gravity reading and it looks like I've hit my expected FG of 1.010 already however Ive just pitched my vodka/vanilla bean mix and will leave it for another 10 days before bottling.

The brew tasted good when I took the reading, I'll let you know how the final product rates sometime around new year.

 

Cheers

Peter

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Hi Peter, for my 2 bobs worth, the stir plate is to aerate the yeast. instead of having to shake it every so often you just sit it on the stir plate and let it do the work for you. I have made a starter using this method and like you found it started very quickly after pitching and finished earlier. Kieran

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G'day pcmax.

 

did you put a speed controller on it? I bought two speed controls for computer fans off ebay.

The first worked great when I plugged it into one fan. When I added a second fan it burnt out.

I've still got the second speed controller to use when I build my stir plate. I'd like to add one

to the two fans I have in my brew fridge though. I reckon they go too fast on full throttle.

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My 2c worth, the stir plate also (apart from aerating the starter and keeping the yeast in suspension) forces the outgassing of the CO2 produced, which also encourages faster yeast growth

 

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G'day pcmax.

 

did you put a speed controller on it? I bought two speed controls for computer fans off ebay.

The first worked great when I plugged it into one fan. When I added a second fan it burnt out.

I've still got the second speed controller to use when I build my stir plate. I'd like to add one

to the two fans I have in my brew fridge though. I reckon they go too fast on full throttle.

 

Yes I bought a 1K potentiometer from jaycar (about $2.50) it works but only in about the first 1/4 of the dial range. You just need to move it in very small increments to adjust the speed. I also find that for some reason the more fluid I have in the flask the slower it spins, I guess that's probably basic physics but it's a bit beyond me.

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You really should be using a much lower resistance, like 100 ohms down to 20 ohms to get a wider range of control. Using these pots to control the speed risks burning them out, unstable speeds as the resistance strip heats and cools and being inefficient.. You could buy a more expensive reostat wirewound one, they can handle 5W - 15W generally, but better to build a proper speed controller by adding two extra components, a LM317 variable voltage regulator and a resistor.

 

Some good links here : http://www.stir-plate.com/Build.htm

 

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You really should be using a much lower resistance' date=' like 100 ohms down to 20 ohms to get a wider range of control. Using these pots to control the speed risks burning them out, unstable speeds as the resistance strip heats and cools and being inefficient.. You could buy a more expensive reostat wirewound one, they can handle 5W - 15W generally, but better to build a proper speed controller by adding two extra components, a LM317 variable voltage regulator and a resistor.

 

Some good links here : http://www.stir-plate.com/Build.htm

[/quote']

 

G'day Headman. Have you ever thought about learning English to use as your first language? happy

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You really should be using a much lower resistance' date=' like 100 ohms down to 20 ohms to get a wider range of control. Using these pots to control the speed risks burning them out, unstable speeds as the resistance strip heats and cools and being inefficient.. You could buy a more expensive reostat wirewound one, they can handle 5W - 15W generally, but better to build a proper speed controller by adding two extra components, a LM317 variable voltage regulator and a resistor.

 

Some good links here : http://www.stir-plate.com/Build.htm

[/quote']

 

I'm a bit of an electrical novice but when I went into Jaycar and a electrical wholesalers to explain why I was building and simply needed a variable resistor to control the speed of a 12v fan driven by an bold 5v phone charger they had no idea what I was talking about. The guys at Jaycar wanted to sell me something for about $80 (I can buy a commercial stir plate for that). They claimed that they didn't have anything to control something only outputting 5v but ended up suggesting I experiment with a 1k and 100k potentiometer. The 1k one worked.

I think the 1k one was the lowest they had. Should I go back and ask for a 100 ohm one? Do I ask for a 100 ohm pot or is there another term? Not sure of the eleco lingo!!

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Since I'm a lazy arse at times when it comes to DIY projects, I decided since my current stirrer keeps playing up and refusing to spin the magnets for some reason, I would buy another one.

 

I decided on the Digital Homebrew Yeast Forge model this time around. I'd seen it talked about on AHB and was actually waiting for it to be available. It appears to be of decent quality, but the deciding factor for me was that it is also heated, which means I'll be able to make ale yeast starters in winter much more easily, and can heat up lager starters as well to get them done faster. The heating function can also be turned off when not needed and just used as a normal stirplate, such as at this time of year.

 

I'm hoping it arrives in time for the next starter I have to make in a couple of weeks time but of course it is the festive season so it may take a little longer. Depends when they send it I guess.

 

Cheers

 

Kelsey

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I think the 1k one was the lowest they had. Should I go back and ask for a 100 ohm one? Do I ask for a 100 ohm pot or is there another term? Not sure of the eleco lingo!!

 

Yes that would work, or the full name is potentiometer. As I mentioned anywhere from a 20 ohm to 100 ohm pot would give you a better range of control , but the standard pot probably won't last long as it's not designed for these levels of electrical current.

 

You may find that the fan is actually 12v and it will run much better with more torque and speed at this voltage. Check the sticker on the motor, all the ones I have seen are 12v. At 5v you woudl have trouble spinning up a bar in solution and getting a whirlpool happening in all but very small containers.

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