Magnetic Stirrer

Im looking to get a stir plate, and want to know what everyone else is using, as well as what the best low cost one would be to buy. I found a Hanna HI 190 for $67 and want to make sure its big enough. It handles 1 liter. Any thoughts?

What are you stirring? I've never heard of a homebrewer using a magnetic stirrer as they use in labs.

Its for making better yeast starters. It allows for generating more yeast from your starter by constantly stirring the starter and mixing in more air.

Do you use oxygen in your starters too, Tony?

I havent yet, as Im just now getting a stirrer, but thats next on my list.

i think you might have a lot more toys than the rest of us, Tony.

I shake my starter every time I walk past it. That's as fancy as it gets around here.

-walker

I just started using a stir plate this year and can wholeheartedly recommend it. My set up is like this:

3 liter Erlenmyer flask
Hanna Magnetic Stirrer (model HI 190 M)
Foam Stopper
38 mm stir bar

Even though the specs on the stir plate says it only handles 1 liter, the 3 liter flask fits on the plate just fine and I make 1.5 liter starters all the time with no problems. I found the 25 mm stir bar a little on the wimpy side (at least for the volumes I use for starters) and I now use the 38 mm with better results. Buy extra stir bars, I garauntee you will pour one into a carboy at least once. To prevent this, get a good strong magnet somewhere and keep it handy so when it's time to pour the starter into the carboy, you use your magnet on the outside of the flask to hold the stir bar in place so you don't pour it into the carboy.

I LOVE using the stir plate. I can make a starter in about 1/2 the time it used to take, I dirty almost no equipment, and I don't need any sanitizer. Everything goes into the flask (DME, water, stir bar) which is brought to a boil. I put the foam stopper into the neck of the flask and let the steam during the boil sanitize it. The starter ferments out in about 36 hours and gives me as much yeast from 1.5 liters as I used to get with a full 2 liter starter.

A stir plate is definitely an optional piece of equipment, but if the prospect intrigues you at all, I would definitely recommend it.

Prosit!

What's a foam stopper?

El Pistolero said:

What's a foam stopper?

Click to expand...

Sorry. It's a foam plug that fits into the neck of the flask. The foam structure allows the CO2 to vent out but keeps the nasties out.

http://www.northernbrewer.com/yeast-handling.html

Scroll down to Foam Stopper.

Prosit!

that's very bizarre. If gas can go through it, nasties could, too. Granted, the chance is LOW, but it's much larger than the chance with a tight-fitting rubber stopper!

Plus, it won't keep air from getting in, so it seems to be of dubious value to me.

-walker

I don't even make a yeast starter, I just whack the yeast in straight from the packet. Its never let me down, and the only time I did rehydrate the yeast it didn't really make a difference.

But if C02 is going out O2 can't come in?

orfy said:

But if C02 is going out O2 can't come in?

Click to expand...

For a starter it doesn't matter. A starter is all about yeast. Oxidation is all about beer. The starter wort is decanted off the yeast anyway. No worries.

Prosit!

Walker said:

that's very bizarre. If gas can go through it, nasties could, too. Granted, the chance is LOW, but it's much larger than the chance with a tight-fitting rubber stopper!

Plus, it won't keep air from getting in, so it seems to be of dubious value to me.

-walker

Click to expand...

As mentioned previously, aeration or oxidation of starter wort is a non-issue. We only care about the yeast, not the wort. As for gas versus nasty bacteria, the bacteria and such are much larger than gas molecules and can't make it through the winding path through the pores of the foam stopper. However, you should always practice what you are comfortable with. If a rubber stopper is your standard MO, then stick with it.

Yeah, OK, I can see your point, but still... buying a special plug JUST for making starters?

then again... I'm talking to people here that use magnets and special rods in their starters to stir it up, so....

-walker

Just another in a long line of optional beer tools with pros and cons. Although this one did require more $$$ than usual, I really like the results, plus the time and convenience factor was worth a lot to me. I think the right tool is worth the money in almost all cases; you just have decide what your definition of "right tool" is.

Prosit!

more power to you!

One of these days, when I get closer to retirement (hell, that's only 30 years away) I hope to have a big lab in my basement that Dr. Frankenstein would envy.

-walker

First off...the plugs are all of 80 cents! I saw then on Nothern Brewers website, and I will be picking a few of them up.

Also, thanks tnlandsailor, as I wondered if the 190 M would handle a larger flask. Also, thanks for the tip on the stir bar. Looks like all my questions and wonders have been answered!

I ended up looking on eBay and picked up this one for $16.50

Hi, I'm new to these forums so be gentle

Unless using dried yeast, I always use a stir-plate with my starters.

IME, to get maximum yeast growth you need continuous stirring AND continuous oxygenation. Using the stir-plate alone does yield more yeast but does not seem to reduce the time taken for the starter to "poop out".

So lets say without a stir-plate, your starter is done after 3 days and yields 200ml of yeast. With a stir-plate, I reckon you'd have 250-300ml but it would still take 3 days to complete. Add continuous aeration and after 2 days you'd have around 500ml of yeast.

I purchased a Hanna Instruments HI 190M about two years ago. A stirrer is great for the big beers. I brew two to three big beers a year (Plato 20 degrees +), culturing starters for a couple of days. So, the 190M stirred for maybe two weeks. It burned out readying a starter for the Christmas batch. My next stirrers will not be Hanna Instruments. ...Walker is right, swirl your flask by hand works well.

Much cheaper stir plate. This is just one guide of many out there:
http://www.donosborn.com/homebrew/stir_plate.htm

NE NE NE Necro Bump!

Hah, woops. Just saw the latest post and didn't notice the thread was so old