Why a stir plate???

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DPBISME

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So I have been brewing for 12 years and made the leap to all grain brewing a year ago.

I brew 10 gallon batches and use Nottingham a lot... two packets for 10 Gallons of wort.

I now am really trying hard to:

  • brew beers true to style
  • Take good notes to reporduce the process/beer
  • Learn something new each time I brew

I now have a question as to why folks use a stirrer-plate wen making a starter?

  1. Why can't i just cook the starter on the stove.
  2. Cool it down
  3. Pour it in to it's container
  4. Aerate
  5. Cast the yeast
  6. Shake it up


The only advantage I see is that if you do eveything in "flask" is sanitation.

Am I missing something?

DPB
 
Why you use a stir plate is different than doing things with a flask. Two entirely different items - as I boil my starter in a pot and pour into the flask but I use a stir plate. Stir plates really help increase your overall growth and density. Check out Mr. Malty for more information and do some searches on this site. Key is stir plates are used when you're using liquid yeast – if you're going to use dry yeast they aren't appropriate.
 
From what I understand, I do not own a stir plate, but it helps keep the aerating the starter, giving the yeast more oxygen to reproduce.

Yeast starters are only recommended for liquid yeast, as the cell count isn't as high as a dry yeast.

Alternatively, you can just shake the crap out of it every time you walk by. This is my method. I make good beer with it.
 
makomachine said:
Why you us ewith a stir plate is different than doing things with a flask. Two entirely different items - as I boil my starter in a pot and pour into the flask but I use a stir plate. Stir plates really help increase your overall growth and density. Check out Mr. Malty for more information and do some searches on this site.
Click to expand...

Thanks for the response:

I guess I am trying to figure out if they do "...increase your overall growth and density..." why the difference?

DPB
 
I'm having a heck of a time with the iPad app for this site as it keeps posting when I'm not completed with my update. Sorry for the multiple changes.

Stir plates helps with aeration, and I'm not into all the science around it, but I believe it's more so keeping the yeast in suspension. Why people use them is due to the fact that they can use a single vial of liquid yeast and get more growth for the quantity of starter that they create. It's an efficiency thing. Go to Mr. Malty.com and you can play around with what predicted values you need using a stir plate versus doing a conventional starter. Jamil has done a lot of research in this area and I think it's pretty clear that you'll get more growth on a stir plate than you will with a conventional starter.
 
they help increase the growth because they constantly introduce oxygen which is an essential part to yeast reproduction. Yeast aerating through shaking is a viable method although it is not as effective because you are only periodically shaking. You would need to do it constantly to replicate the action a stir plate provides. They also keep the yeast constantly in suspension
 
Stir plates continuously agitate the starter. It helps the yeast propagate. You get a quicker healthier starter. It also allows you to make a smaller starter.

Check out mrmalty.com and plug in some numbers.

for example: for a 1.050 beer

simple starter (no shaking) = 1.63 liters
simple aerated with O2 = 1.22 liters
intermittent shaking = 1 liter
continuous aeration = 1 liter
stirplate = 1 liter
 
cmybeer said:
they help increase the growth because they constantly introduce oxygen which is an essential part to yeast reproduction. Yeast aerating through shaking is a viable method although it is not as effective because you are only periodically shaking. You would need to do it constantly to replicate the action a stir plate provides. They also keep the yeast constantly in suspension
Click to expand...

So,, when you do the "stir-plate" method you aerate more than once?

I assumed that when using a stir-plate you aerated once just like when brewing....
 
+1 on Mr. Malty. Using Jamil's web site and calculations, as well as reading his book "Yeast", has had the largest positive impact on the quality of my home brews of anything I have done. I was chronically underpitching and under aerating before reading this. I now use the Mr. Malty calculator for every batch, have recipes for yeast starters from .5L up to 5L in half liter increments in my BeerSmith software, and aerate my wort with pure oxygen before pitching.

If you check out Mr. Malty, you will understand that a stir plate is not required. However, he gives you calculations on how much yeast to put in a starter for any given common method (stir plate, occasional shaking, doing nothing). You will see that using a stir plate requires the least amount of starter yeast and the least amount of time to fully ferment.

BTW, his reason for not creating a starter with dry yeast is simply economical. Dry yeast is usually inexpensive enough to simply buy more packs and pitch them than mess around with a starter. Otherwise, he doesn't mention any harm in creating a starter with dry yeast. Still, the Mr. Malty calculator will tell you how many packs of Notty to pitch for any given wort.

Good luck!
 
BrewingSailor said:
+1 on Mr. Malty. Using Jamil's web site and calculations, as well as reading his book "Yeast", has had the largest positive impact on the quality of my home brews of anything I have done. I was chronically underpitching and under aerating before reading this. I now use the Mr. Malty calculator for every batch, have recipes for yeast starters from .5L up to 5L in half liter increments in my BeerSmith software, and aerate my wort with pure oxygen before pitching.

If you check out Mr. Malty, you will understand that a stir plate is not required. However, he gives you calculations on how much yeast to put in a starter for any given common method (stir plate, occasional shaking, doing nothing). You will see that using a stir plate requires the least amount of starter yeast and the least amount of time to fully ferment.

BTW, his reason for not creating a starter with dry yeast is simply economical. Dry yeast is usually inexpensive enough to simply buy more packs and pitch them than mess around with a starter. Otherwise, he doesn't mention any harm in creating a starter with dry yeast. Still, the Mr. Malty calculator will tell you how many packs of Notty to pitch for any given wort.

Good luck!
Click to expand...



Thanks for the recommendation... I will look.
 
DPBISME said:
So,, when you do the "stir-plate" method you aerate more than once?

I assumed that when using a stir-plate you aerated once just like when brewing....
Click to expand...

Using a stir plate will continuously aerate the starter. You use a sponge or similar porous bung or cover. The vortex created by the stir plate will constantly pull in oxygen and put it in the solution. Stirring also gives the yeast the best opportunity to contact the oxygen, creating rapid and healthy growth.

Not to beat a dead horse, but Mr. Malty. :)
 
DPBISME said:
Thanks for the recommendation... I will look.

Also: I searched the web for "yeast reculturing from slants" and there were a bunch of things to read and I read this one: http://www.realbeer.com/spencer/yeast-culturing.html

The only thing I have not found yet is why "slants... assure maintenance of the original generation" but I will continue to see if I can figure it out...
Click to expand...

The way I understand it, and to give an anology, when you use slants you are always making a copy from the original. If you think of photocopying a picture, if you make 10 copies of the original they will all look the same, and very, very close to the original. However, if you make a copy of the original, and then a copy of that copy, and so on, the 10th copy will be quite different. This is, in essence, what happens when you continuously repitch yeast. Eventually, the yeast becomes something entirely different than what you started with.

The book "Yeast", written by Dr. Chris White (founder of White Labs) and Jamil Z., explains in detail everything you have asked in this post, including culturing from slants. I highly recommend it.

Again, best of luck!
 
So I think the thing I was missing about using a stir-plate was that it is continous...

I would have thought yeast liked it kind-a mellow and still but I guess it does not mind spinning around in circles...

Thanks,

DPB
 
I wanted to also mention another good yeast calculator, simply called YeastCalc...it's advantage is it allows you to calculate sequential step ups.

One thing I've been curious about though, and wonder if anyone else had a good answer...the calculators have options for simple starter, simple w/ O2 injection, and continuous (stir plate). What happens if you use both oxygen and stir plate? Is there some further benefit/increase in cell count from giving a shot of oxygen to aerate, plus the stir plate, or does the stir plate maximize things by itself? If there is some benefit, how do you calculate this?
 
biochemedic said:
I wanted to also mention another good yeast calculator, simply called YeastCalc...it's advantage is it allows you to calculate sequential step ups.

One thing I've been curious about though, and wonder if anyone else had a good answer...the calculators have options for simple starter, simple w/ O2 injection, and continuous (stir plate). What happens if you use both oxygen and stir plate? Is there some further benefit/increase in cell count from giving a shot of oxygen to aerate, plus the stir plate, or does the stir plate maximize things by itself? If there is some benefit, how do you calculate this?
Click to expand...

My guess would be that a stir plate will introduce air to the yeast, air is only 21% o2. Introducing 99% o2 to such a small amount of wort might be be hard to calculate. 99% o2 required for 5 gallons of wort only takes about 15-20 seconds depending on you regulator setting. Just my .o2
 
BrewingSailor said:
BTW, his reason for not creating a starter with dry yeast is simply economical. Dry yeast is usually inexpensive enough to simply buy more packs and pitch them than mess around with a starter. Otherwise, he doesn't mention any harm in creating a starter with dry yeast. Still, the Mr. Malty calculator will tell you how many packs of Notty to pitch for any given wort.
Click to expand...

Dry yeast are actually packed with everything they need to ferment beer. Any starter activity will actually hurt, not help, viability. At least, that's my recollection on the topic - believe it was discussed on a Brew Strong episode. Rehydrate only with water - as the pressures of wort can damage them as they draw liquids in through their cell walls to rehydrate. (My laymans, likely brutalized, summation of the issue.)
 

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