Is there a reason to make starters in a flask?

Is there anything special about flasks that make them better for starters than other types of glassware - a growler for instance.
This is probably a pointless question since I just proved to myself that a gallon growler works just as well as a 2L flask. There is plenty of room so that there is not worry about the starter blowing out and growlers are much cheaper (4 1g growlers for $17 at LHBS) than the flasks ($18 for on 2L flask). This was for a 5g brew, so I see the cost of a flask for making a 4L starter for a 10g brew getting ridiculous - Is there any reason why I can't just use my 2.5g carboy for that?

borosilicate lab glass can be boiled and cooled rapidly. so you can boil the starter with foil or a foam stopper atop the neck for the 15 minutes, then immediatly remove from heat and place in ice water bath. it remains sterile throughout.

I was just thinking the same thing this weekend but for a different reason. Since many people use foil, flasks are known to foam-over easily, and we want a free exchange of air; why not just use a beaker? Seems a beaker would foam-over a LOT less easily AND we get a better exchange of air. So...why flasks?

No reason not to use a beaker or whatever as long as you can sterilize it and keep it that way.

In the lab we use flasks because they are easy to "seal" and when on a shaker, the faster you rotate them the more the liquid "climbs" up the walls of the container. The tapered walls of the flask help to prevent this and keep the culture from spraying out the top when shaking at higher rpms.

I use a 1 gallon growler/jug for my 2L starters. I think those who use flasks may use it for use with a stirbar/stirplate. Not all growlers have flat bottoms and it makes it difficult/impossible for a stirbar to, well stir, without being thrown.

Thanks for all of the feedback.

I work in a microbiology lab, so I figured the main reason for flasks was the heat resistance so that you can use them to boil the starter wort and cool it in the same vessel, keeping everything contained. But as far as home brewing goes - nothing is really sterile, just sanitized. So, why would you pay for an expensive flask when you can boil the starter wort in a pan on the stove, cool it, and then transfer it to an inexpensive growler that has been sanitized with Star San. (luckily my growlers have flat bottoms so they don't throw the stir bar and the LHBS sells drilled corks for them)
Having done this myself, I would recommend it to anyone cringing at the price of flasks as I was. I got four 1g growlers for the price of one 2L flask. I'm also making a DIY stir plate this weekend for frugality sake.

JoeJones said:

Thanks for all of the feedback.

I work in a microbiology lab, so I figured the main reason for flasks was the heat resistance so that you can use them to boil the starter wort and cool it in the same vessel, keeping everything contained. But as far as home brewing goes - nothing is really sterile, just sanitized. So, why would you pay for an expensive flask when you can boil the starter wort in a pan on the stove, cool it, and then transfer it to an inexpensive growler that has been sanitized with Star San. (luckily my growlers have flat bottoms so they don't throw the stir bar and the LHBS sells drilled corks for them)
Having done this myself, I would recommend it to anyone cringing at the price of flasks as I was. I got four 1g growlers for the price of one 2L flask. I'm also making a DIY stir plate this weekend for frugality sake.

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I pretty much agree. I also do work in a lab, so I have about 4 2L "growlers' and 2 4L "growlers" for free.

JoeJones said:

Thanks for all of the feedback.

I work in a microbiology lab, so I figured the main reason for flasks was the heat resistance so that you can use them to boil the starter wort and cool it in the same vessel, keeping everything contained. But as far as home brewing goes - nothing is really sterile, just sanitized. So, why would you pay for an expensive flask when you can boil the starter wort in a pan on the stove, cool it, and then transfer it to an inexpensive growler that has been sanitized with Star San. (luckily my growlers have flat bottoms so they don't throw the stir bar and the LHBS sells drilled corks for them)
Having done this myself, I would recommend it to anyone cringing at the price of flasks as I was. I got four 1g growlers for the price of one 2L flask. I'm also making a DIY stir plate this weekend for frugality sake.

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But if you boil in the flask and cool in the flask it should be as close to sterilized as you can get. Sterile is sterile but sanitized is a matter of degree and to many, especially when dealing with yeast, the more sanitized the better. Having said that I boil in a pot and then pour the boiling hot wort into the sanitized flask (the flask is placed under hot tap water for a few seconds to preheat it). I only do that to avoid boilovers.

<--------Another one that works in a lab (but I'm just an engineer and don't do the actual lab work).

As mentioned above... nice flat bottom for the stir bar.

I agree with both the boiling in-flask and the flat bottom for the stir bar. I have a hell of a time getting my stir right in my growler, but I haven't yet been able to bring myself to get a flask. Maybe once my keezer is done...

I don't care to boil in a flask, with the risk of a wort volcano in your face. I use this exclusively. It's a half a gallon and works with a stir bar. If you can't transfer wort from a pot to a sterilized vessel without fear of infection, you can't make beer.

How big are the stir bars everyone is using? I've got one that is about one and half or two inches long and pretty fat. I do realize I'm going to get reamed for that sentence. Maybe the size of the stir bar increases the stability.

IMLE, it appears that the stirbar needs to be about the same length as the distance between the magnets in the stirplate. Otherwise one magnet in the stirplate tends to pull the stirbar off-center. I use the stirbar included with the stirplates.com stirplate (1-5/8" long when tergid) but I tried longer stirbars and they didn't work as well.

Here's something from the stirplates.com FAQ:

Q: I already tried making my own stir plate and it just never worked right. It would always stop or throw the stir bar. How do I know yours will be any better?
A: Good question. First, mine is built around the LM317 adjustable voltage regulator so it supplies very consistent voltage to the motor. Second, I align the drive magnet and test each stir plate with a 2L flask before shipping. Third, I limit the top speed of the motor to help reduce thrown stir bars. I also encourage you to check out my eBay feedback rating and what others have said there and on the brewing forums.

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Don't keep it at high speed, just enough to make a little vortex is all it takes.

JoeJones said:

How big are the stir bars everyone is using? I've got one that is about one and half or two inches long and pretty fat. I do realize I'm going to get reamed for that sentence. Maybe the size of the stir bar increases the stability.

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No there is a quote for ya.

To you people saying that a flask can be used to boil wort - can you put it directly on top of the (electric) stove element? Or do you need a thick aluminum plate, or can it only be done on open flame?

i would put it in a pan of some sort to assist in more even heat distribution. i use a 316 ss mesh under my flasks on my gas stove... lab practice.

wildwest450 said:

If you can't transfer wort from a pot to a sterilized vessel without fear of infection, you can't make beer.

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+1
Personally, I'd be just fine if "sterilized" was automatically converted by the forum software to "sanitized", since most everyone really means sanitized.
Yep, thats right, boiling != sterilized

I suppose I could pressure cook my flask and wort to sterilize, but I think boiling is close enough, I don't acid wash the yeast either. It's less cleanup for me to just boil in the flask, I use a little foam control so I don't get boil-overs.

Or just buy this
http://www.sciplus.com/singleItem.cfm/terms/14345/emailid/133

interesting $2.00 semi-stirplate.

wildwest450 said:

If you can't transfer wort from a pot to a sterilized vessel without fear of infection, you can't make beer.

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For me that's not it at all, I don't like getting any more things dirty and having to clean up any more than is absolutely necessary!

I don't think a flask is necessary, but it's the right tool for the job. Its like you can use a crescent wrench or a pair of pliers to loosen a nut, but I prefer to use a crescent wrench.

I think the Erlenmeyer flask has several features that make it best suited for growing up bugs. Most have all ready been mentioned. Borosilicate can be heated and cooled rapidly, and the flat bottom works best with a stir bar. Some other things that have not been mentioned is that the wide base of the flask provides a larger surface area and in turn better O2 exchange. Another benefit is that with a small opening dust carrying contaminates have less of a chance to fall in to the flask when you have it open.

I like them too, because I'm lucky and have access to an autoclave here at work (I'm a lab rat). I would not put a growler in the autoclave.

Give me an Erlenmeyer flask, any day.
I personally get off on the MSF (Mad Science Factor).
And I'm told that I look downright sexy holding a bit of lab equipment.
Wouldn't trade that for a jelly jar. ;-)

I understand where you’re coming from, but I respectfully disagree on a few points.

First, the O2 exchange happens at the surface of the liquid, not at the bottom. So the wide base of a flask has noting to do with it. In fact, the neck of the flask is tapered so that there is actually less surface area to exchange gases freely when compared to a 1g jug, growler, whatever. This is especially true when you’re using a 2L flask to make a 2L starter because the flask is nearly full to the top.
Second, the opening on a gallon jug and a flask are basically the same size. Actually, the openings on the flasks in my lab are bigger than the opening of a gallon jug. Not that that really matters. How much is exposed when you use an Ale Pail…
Finally, why does everyone keep talking about sterilizing? Why would you autoclave your flask when every other piece of equipment used for brewing is sanitized, not sterilized.

I get the idea of it looking cool and all, but right now I’m a poor grad college student looking strictly at functionality. Back to one of my original points, a 1g jug is ¼ the price of a new flask. Hell a 2 quart mason jar I probably less than that.

SpanishCastleAle said:

I was just thinking the same thing this weekend but for a different reason. Since many people use foil, flasks are known to foam-over easily, and we want a free exchange of air; why not just use a beaker? Seems a beaker would foam-over a LOT less easily AND we get a better exchange of air. So...why flasks?

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Only if you are using a flask that is too small.

pjj2ba said:

No reason not to use a beaker or whatever as long as you can sterilize it and keep it that way.

In the lab we use flasks because they are easy to "seal" and when on a shaker, the faster you rotate them the more the liquid "climbs" up the walls of the container. The tapered walls of the flask help to prevent this and keep the culture from spraying out the top when shaking at higher rpms.

Click to expand...

bump!
+12345

JoeJones said:

I understand where you’re coming from, but I respectfully disagree on a few points.

First, the O2 exchange happens at the surface of the liquid, not at the bottom. So the wide base of a flask has noting to do with it. In fact, the neck of the flask is tapered so that there is actually less surface area to exchange gases freely when compared to a 1g jug, growler, whatever. This is especially true when you’re using a 2L flask to make a 2L starter because the flask is nearly full to the top.
Second, the opening on a gallon jug and a flask are basically the same size. Actually, the openings on the flasks in my lab are bigger than the opening of a gallon jug. Not that that really matters. How much is exposed when you use an Ale Pail…
Finally, why does everyone keep talking about sterilizing? Why would you autoclave your flask when every other piece of equipment used for brewing is sanitized, not sterilized.

Click to expand...

First of all, if you are filling the flask all the way up, you are using too small of a flask. A 2L flask is good for 1L starters, a 4L is for 2L and a 6L is for 4L. Personally I use my 6L flask most of the time even with 2L starters. This way the wort is vary shallow and gets good gas exchange. The opening does not mater for gas exchange because gases move vary readily from through any opening of a flask or a jar.

I like to autoclave just to give my self a fresh start, I do make Brett starters, and like to keep that out of my regular brewing.

but like I said, you can use what ever works for you, but I'll keep working with my flasks.

JoeJones said:

I get the idea of it looking cool and all, but right now I’m a poor grad college student looking strictly at functionality. Back to one of my original points, a 1g jug is ¼ the price of a new flask. Hell a 2 quart mason jar I probably less than that.

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From a purely functional viewpoint, a flask is certainly not necessary. It's a convenience; worth it for some people, but may not be for others. Hell, for me the simple fact of having less stuff to clean up makes it well worth the $9 my last 2L flask cost me.