Boiling wort for starter right in the flask

2 questions..... I'm going to try to do my first yeast starter and just aquired a 1000 ml flask from school. It's a Kimble KIMAX flask, and I was wondering if I can boil my wort right in the flask? I have a glass top stove, or an electric hot plate. Also how much DME do I use per 16 oz of water for the starter? Can also used dextrose or is this frowned upon? Thanks all

yes, I have done it with their 4 liter flask

I don't know about the flask. Several people recently have mentioned problems about boiling in a flask on an electric stove.
For 16 oz water, you need about 50g or 1/2 cup DME. Don't use dextrose. You need something as close to the brew wort as possible to make a successful starter.

-a.

My question would be how to chill the flask after it's boiled...wouldn't it crack submerged in cold water???

I heard that since the flasks are Lab Grade glass they can handle the heating and cooling well. DO most others just boil in a pot and then dump it into the flask??

I have 2 flasks and always boil in them. Put stir bar in during boil, tool. I let it sit with foil on the top for a while. You can chill with icewater if you are in a hurry. I can't bring myself to put it into the icewater right off the stove, so I let is sit for a few minutes. Then I put in sink with icewater. Never a problem.

Here is how I do it:

Fill sink with water and Starsan

Sanitize equipment

pour water and DME in flask - I just use a cheap scale and do the 10:1 ratio in grams.

Boil in flask on stove

Once I am ready to cool, I dump the all of my ice in the freezer in the (sanitized) water. I immidiately remove flask from stove and put it in the cold water. Trust me the flask can handle this!!!

I am not sure what the fuss is all about but I do this on a electric stove and have no problems whatsoever.

Just remember one thing if you do this method, the water level must be no higher than the level of wort in your starter or the flask will not stand on its own.

This works great for me because my sanitzed water doubles as the sanitizer and wort chilling bath. Less mess, less clean up. Hope this help.

http://en.wikipedia.org/wiki/Borosilicate_glass is good stuff. I re-use the ice packs that ship with yeast for chilling my starter to pitching temps.

I always got a boilover when boiling in the flask.
Now I just boil a little water in the flask to sterilize the stirbar and foam stopper.
I boil the wort in a separate pot for 10 minutes, then pour into the hot flask.

HairyDogBrewing said:

I always got a boilover when boiling in the flask.
Now I just boil a little water in the flask to sterilize the stirbar and foam stopper.
I boil the wort in a separate pot for 10 minutes, then pour into the hot flask.

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Fermcap. You need it.

I put some DME in a flask on my stove, on high yesterday. I forgot about it. No boilover. Fermcap-S. You need it.

passedpawn said:

Fermcap. You need it.

I put some DME in a flask on my stove, on high yesterday. I forgot about it. No boilover. Fermcap-S. You need it.

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I'm glad you like Fermcap, but I don't want to put extra stuff in my beer.

The problem using one on on an electric stove is the uneven heating of the element. Many have and do do this with success, buy in theory, and in some cases, it will cause even the Pyrex to bust. A flame for heating is fine because of the even heating. Perhaps a small propane cooking burner.

HairyDogBrewing said:

I'm glad you like Fermcap, but I don't want to put extra stuff in my beer.

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Hey, ever have a beer at the Gingerbread Man?

HairyDogBrewing said:

I'm glad you like Fermcap, but I don't want to put extra stuff in my beer.

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Hope you like cleaning your stove, then. An electric stove doesn't give you very quick control over the heat, and flasks like to become volcanoes.

Kimax is the same as pyrex and the beakers should be fine to heat.

I had good luck with the electric stove top. I keep the tin foil over it while I boil which seemed to help keep it from boiling over. Actually I don't even aim to boil, probably about 190* and then just let it air cool on it's own.

I've been wondering about using corn or table sugar as well. Maybe with some yeast nutrient to help give it some nitrogen or whatever it needs? I defeinetely plan to experiement with this as I start messing with bigger starters.

It's annoying. Just use a 8qt pot.

It takes FOREVER to heat, FOREVER to cool, and the shape causes boil overs too easily.

grathan said:

I've been wondering about using corn or table sugar as well. Maybe with some yeast nutrient to help give it some nitrogen or whatever it needs? I defeinetely plan to experiement with this as I start messing with bigger starters.

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Wort has mostly maltose, table sugar is sucrose, and corn sugar is dextrose.
You want to make your starter from a malt extract.
Otherwise, the yeast will 'forget' how to process maltose.

Boil 1.5 - 1.75 starters in a 2L flask. Fermcap **greatly** reduces the boil over possibility.

Also I add the stirbar after boil, top with a alum. foil cover and let the flask sit 5 min to pasteurize them. Then into a sink of cold water and ice. Some have reported the stir bar melting when boiling it.

And concerns over adding Fermcap? I use 3 drops from an eyedropper, I am not concerned when added to 5.5 gal of wort.

grathan said:

Kimax is the same as pyrex and the beakers should be fine to heat.

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Pyrex, Kimax, Borosilicate. All safe for heating directly and cooling.

Boil in the flask and avoid boilover by spray bottle, using a bigger flask (don't make a 2L starter in a 2L flask, dummy!), Fermcaps, etc

Best and most sanitary way to do it, folks. If you are building up from a collected sample or from a yeast bank, get yourself a collection of various sizes and this makes stepping easy and sanitary. Steam and boiling wort sanitize the flask and you will stay infection free. You can still stay infection free using normal sanitation practices, but it's just a little more work.



Using cheap electric stove elements can create "hot-spots". The above mentioned materials should still be fine in this environment, but you also risk scorching.

rcrabb22 said:

Some have reported the stir bar melting when boiling it.

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I am not sure about some of the cheaper ones, but the only way I have ever seen one warped is to put it in a hot pan or on direct heat without liquid as the insulator. They are totally inert and safe at boiling temps, but perhaps the hot-spot electric stove aspect could affect it if it sits in just the right spot?

HairyDogBrewing said:

Wort has mostly maltose, table sugar is sucrose, and corn sugar is dextrose.
You want to make your starter from a malt extract.
Otherwise, the yeast will 'forget' how to process maltose.

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+1.

By keeping them in the same environment they'll see in your fermenter, you will be sure to select for yeast that will do what you want them to rather than mutations that happen to eat sucrose or dextrose really well.

I boil in a 2L Erlenmeyer because it's one less thing to clean. I use an anti-foamer like Fermcap-S, and I've found that wide mouth Erlenmeyers are a bit better than narrow ones at controlling boilover. (My wide mouth 2L flask takes a #13 stopper, whereas the narrow one takes a #10.)

EDIT: I always boil the stir bar as well. Don't want to risk it as an infection vector, and any lab stir bar should be boil safe.

I always boil mine in the flask. I purchased a 3000 ml one after my other one broke on the stove. Real big mess. After that one breaking, I took a look at my process and made a square out of copper wire. I place the copper square on the burner and then place the flask on top of it.
Not sure if this was a good fix or not, but I havent broke this one yet.
I always add the stir bar to the boil and let it boil for about 5 minutes and then let it set a while, then I submerge it in a ice bath.
While it is fermenting I just put a doubled over piece of plastic wrap with a rubber band to keep it on.
Works great, no problems.

Just used my new monster 5L flask yesterday. Boiled in SS pot and then poured off into StarSan sprayed flask in sink. Immediately started to fill sink with cool water and then added ice after a minute or two.

Never had such a raging starter fermentation before. Also first time using a tiny bit of White Labs yeast food.

btw - if using pyrex on electric element you should get one of those metal rings (Trivet -looks like bent coat hanger) as they even out the heating and prevent shattered pyrex, which I have seen happen.

samc said:

btw - if using pyrex on electric element you should get one of those metal rings (Trivet -looks like bent coat hanger) as they even out the heating and prevent shattered pyrex, which I have seen happen.

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I literally use a coat hanger. Just make sure it has NO PAINT ON IT (that sucked), break it into two or three pieces, and bend them to the desired shape. They go right on the burner, between the element and whatever your heating. Works really well at preventing scorching, both in the flask and in the brew kettle. If you just boil water, you can easily see the difference -- no more distinct ring of bubbles at the bottom of the kettle (the bubbles are much more diffuse and evenly spread around).

samc said:

Just used my new monster 5L flask yesterday. Boiled in SS pot and then poured off into StarSan sprayed flask in sink. Immediately started to fill sink with cool water and then added ice after a minute or two.

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Yep, I have been looking for 5L and 6L flasks. There really is no reason you can't use a plain ole' beaker, too. Just need a bigger piece of foil to cover it.

Lately I've been stepping up my yeast but my largest flask is 2L and that just isn't big enough for 13-15 gal batches, so for the final step I have to boil in a pot and into a 1 gal jug (still not technically big enough but I still average 6-8 hr lag times so I'm not too worried.

+1 on fermcap. That stuff is magic.

I would not use a flask on a electric coil. The glass top electric is safe.

I cool in an ice bath with no problems.

I did not know you could boil the stir bar. Thank, I have to start doing that.

HairyDogBrewing said:

I'm glad you like Fermcap, but I don't want to put extra stuff in my beer.

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FYI, I've been told it falls out during the ferment, and doesn't actually end up in your beer any more than the airlock or your mash paddle does. It's food-grade silicone (plastic). But I understand your position completely. You just might look into it a bit more before you write it off.

BTW, I've spent some time in Mechanicsburg.

For those of you who (like me) boil your stir bar magnets, you may want to check out http://www.rare-earth-magnets.com/t-magnet-university.aspx #8
Apparently some magnets can lose their magnetic properties if exposed to temperatures > 80C. Over the past 5 years, I've gotten through about 6 stir bars that have just stopped working. (Last time I researched this, I found mention of 70C as the temperature at which magnetism could be destroyed.) Perhaps I should think of another way to sanitize them, but for the cost of 1 magnet per year, I'm not too worried. It may however be worth paying a bit more for a magnet with a higher temperature tolerance.

-a.

As it says in your link, temperature-induced degradation varies by magnet type. NdFeB magnets demagnetize around 80C and are pretty susceptible to permanent magnetization loss. By contrast, most AlNiCo magnets have Curie temperatures upwards of 500C! (NdFeB tend to be substantially stronger than AlNiCo, though.)

I'm confused. The magnet is inside the stirplate box. The bar is not a magnet. At least mine aint.

Most stir bars are permanent magnets, but if your stir plate's magnet is strong enough you can sometimes get away without it.

kwantam said:

Most stir bars are permanent magnets, but if your stir plate's magnet is strong enough you can sometimes get away without it.

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yep

I've boiled my at least 20 times. It's spinning juniper berries behind me right now.