PSA - Boiling Starter Wort in Flask

[str1p3s]

I'm sure the title has given a clue as to what I'm about to say...but here goes.

I've read in many places that many home brewers boil their starter wort in the pyrex flask directly on their stove top. I was nervous about it at first, but finally came around and have done it probably 6 or 7 times now.

No more. Yesterday I was trying to boil a 3.5L starter for a Vienna lager plus some extra to harvest for later in a 5L flask. Heard a cracking noise, immediately knew what was happening, tried to pull the flask from the stove over to the sink and the whole bottom fell out.

3 problems with this:
1) Brand new laminate flooring that I just finished installing a few weeks ago
2) Brand new glass top stove
3) Wife was home

Wort baked onto the new stove. The rest flooded down the sides and onto the new floor and into the edges against the wall and seeped under the floor planks. My wife and I cleaned it up the best we could as fast as we could and she was late for work.

Later that evening, after a LONG day of scraping burnt wort off the stove and repeatedly mopping the floor to get rid of stickiness, I decide to crack open an Oktoberfest I had bottled and found out why some bottled homebrews are called gushers. Luckily all the beer/foam stayed on the counter and off the floor and walls this time. Great ending to a great day!

 

[RPh_Guy]

Bummer!

German Pyrex?

 

[Jag75]

I'll never forget the first time I had a starter boil over onto our stove . Its electric glass top and your right , it's a booger to clean up. Needless to say my wife wasnt too happy . Now all my starters are canned . Simple and quick . They are worth their weight in gold imo.

 

[kgranger]

Is your stove electric? If so, they heat the glass unevenly and can cause hot spots, cracking the glass. If you have a gas stove with good control over the flame, you can gently heat the flask with no issues, as the flames tend to wrap around the base more evenly.

 

[CJ-3]

I heated my flask on a gas stove and then like the complete idiot I am put it directly into an ice bath.
Broke a brand new flask.

#YouAreNotAlone

Maybe we should have a broken flask thread as well?

 

[Robert65]

Well, this thread https://www.homebrewtalk.com/forum/threads/5l-flask-broke-during-boil.668864/ had just about convinced me to go back to boiling and chilling in a pot instead of flask. Now completely convinced. Thanks.

 

[kevin58]

Been there done that. They will break on gas burners too. Even if they didn't break, the tall, narrow necks accelerate boil overs.

 

[One Eye Ross]

as a former clinical chemist.....I feel your pain. Have lost a few things myself. Using a bunsen burner helps keep things under control but aren't a sure thing, either.

 

[Vale71]

1) Wife was home
2) Brand new glass top stove
3) Brand new laminate flooring that I just finished installing a few weeks ago

Rearranged in the correct order of importance for you...

Duran flasks should be particularly durable and rugged but the price tag is enough to give most homebrewers nightmares:

http://www.duran-group.com/en/produ...ssware/super-duty-erlenmeyerkolben.html#c3606

 

[wepeeler]

Pyrex is fine to heat on a gas burner and transfer directly to an ice bath. The issue here seems to be your electric stove top. There are warnings against using the pyrex flasks directly on an electric stove, both coil and glass.

 

[kh54s10]

Been there done that. They will break on gas burners too. Even if they didn't break, the tall, narrow necks accelerate boil overs.

And with the narrow neck the rising foam will get to the top in a second.... And could spew out the top with force. Be very careful. Don't grab the flask with a bare hand to get it off the heat! (this statement is not from personal experience other than seeing how quickly foam rises in a flask)

Pyrex is fine to heat on a gas burner and transfer directly to an ice bath. The issue here seems to be your electric stove top. There are warnings against using the pyrex flasks directly on an electric stove, both coil and glass.

I wouldn't say that. Each heat cycle will weaken the glass slightly - even with Pyrex. It is a better glass for heating but not immune to the problem.

The main problem with electric ranges and the glass top is that there is a coil the heat directly above the element is hot the space between the coils is cooler. This causes uneven heating of the flask bottom causing areas to expand more than other areas weakening the flask. A glass top stove is a little better since the flask is raised off the burner a bit.

My main reason to heat in a pot and transfer to the flask for use on a stirplate is the risk of an explosive boil over when boiling in a flask. It is much easier to control the rise of the foam in a pot.

 

[Robert65]

Using Fermcap, I've never had a problem with foam in the flask. (Without Fermcap, I've never got any farther into making a starter than the volcano on the stove part.) But having it pointed out that even the best borosilicate glass will not be immune to stress over time drives home, for me, the idea that tempting an inevitable fate is just not worth it when I have a perfectly good pot and funnel on hand.

 

[str1p3s]

For all you funnel users, do you chill in the pot and then pour into the flask? Or chill in the flask? If so, what material is your funnel made from? Any worry that it can handle boiling or close to boiling temps? Or do you turn off the heat and let it cool before pouring into the flask? Pouring from pot to funnel was the PITA I was trying to avoid by boiling in the flask.

 

[day_trippr]

fwiw, I boil and chill in a pot and pour directly into a sanitized 2 or 5 liter e-flask positioned in the sink, and rinse off any spillage.
No drama...

Cheers!

 

[deadwolfbones]

I just mix the water and DME at room temp in a big Pyrex measuring cup, microwave until ~180F, cover with sanitized foil and chill to correct temp, then pour through a sanitized funnel into my sanitized flask. Always works, never an infection.

 

[Robert65]

For all you funnel users, do you chill in the pot and then pour into the flask? Or chill in the flask? If so, what material is your funnel made from? Any worry that it can handle boiling or close to boiling temps? Or do you turn off the heat and let it cool before pouring into the flask? Pouring from pot to funnel was the PITA I was trying to avoid by boiling in the flask.

If I boil in a pot, I chill in an ice bath in the pot. Like you, I wanted to avoid pouring chilled wort, but now I'm thinking, hey, gotta aerate anyway, and the stir plate is going to draw in the same air. Beats shattered glass. My funnel is a big plastic one from the LHBS. I sanitize it and the flask first. It's the same funnel use for hitting a 1L flask when I harvest slurry from a 10 gallon corny. Maybe @day_tripper can hit a flask without a funnel, but my aim with a little pot isn't that good, let alone a fermenter!

 

[kh54s10]

I bring wort in a pot just to a boil. Put the lid on, let it sit on the stove top for a little while then put the pot in the freezer. When cool I pour through a sanitized funnel into my sanitized flask. No worries about temperature with the glass or plastic.

 

[SEndorf]

Welcome to the "I-boiled-the-starter-in-my-flask-ONCE" club !
Membership is growing......

 

[day_trippr]

[...]Maybe @day_tripper can hit a flask without a funnel, but my aim with a little pot isn't that good, let alone a fermenter!

My accuracy has oft proven imperfect, hence positioning the e-flask in the sink first
Still, point being, repercussions are virtually nil.

I bought The Spousal Unit a completely new gut-to-the-studs-and-underlayment kitchen two years ago.
Hella money involved, looks spectacular.
No frickin' way I'm creating sugar volcanos therein!

Cheers!