[dublulovesbeer]

Hey everybody, this is my first post here and I just became an AHA member. I was wondering if anyone else has run into this, I bought second-hand equipment from a coworker including a 9 gallon brew kettle. When I tried to boil water as the water reached boiling it started shaking like crazy, and I had to switch it out to to a smaller one for my last batch (I'm using a standard electric stove burner). My problem is I'm about to do my first all grain, a Kolsch, and that little pot isn't going to cut it. Is this pot warped or is it too wide for the electric stove burner I'm using? The bottom of the pot doesn't look bent or eroded. In either case this will determine whether I have to go buy a new brew pot or one of those outdoor burners (I've been thinking about getting one anyway). Thanks!

[morticaixavier]

Weird, I have never heard of anything like that!

it could be that the element is too small so there is too much hangin over the edges. do you have anything heat proof that you could use to support the edges of the pot?

[denny]

I used to have a pot with a warped bottom that did that.

[euge]

IIRC mine used to shiver on the electric element from time to time. Could be the pot warps enough when hot and in contact with the element or some sort of resonance is developed due to contraction and expansion of the element.

Also, you make a good point- the pot might be too big for the element itself to support the kettle. Might be a trifecta of conditions that's causing it. Sounds bad. Hmmm I wonder if your co-worker had the same problem with the kettle.

[Slowbrew]

IMHO

A 9 gallon pot is a pretty large load for a standard electric burner to handle.  You may be getting hot spots (burner, stove top anything else close enough to heat up) that, along with some warping, might cause it jump around a bit.  I've seen inexpensive pots do this on electric burners back when I was in college but have never seen it on gas.  I would probably look into the outdoor burner and move out of the kitchen if it was me.  I don't think my wife could have been happier than the day my brewery moved to the garage.   

Paul

[ryang]

I heat my mash/sparge water on the electric stove with a 30qt pot and boil on my turkey fryer with a keg.

The kettle on the stove shakes.  I figured it's from the convection of the water moving around and making the pot shake.  I don't pay much attention to it.  It certainly doesn't help that the kettle is so much larger in diameter than the element.

I can't really think of any reason why it would be bad for the element.  It rests on the element pan, and it's on med-high heat which is normal.

[Hokerer]

Yeah, just heating water to boiling for our regular cooking, there seems to be a certain temp range where the pots want to do a jig.  We just live with it.

[dublulovesbeer]

Weird, I have never heard of anything like that!

it could be that the element is too small so there is too much hangin over the edges. do you have anything heat proof that you could use to support the edges of the pot?

Heh, well when it happened I sort of panicked and tried weighing the handles of the pan down with dumbbells....came close to a disaster haha.

If you mean could I wedge something under the sides of the pot, but wouldn't that not heat it up properly?

I might go for the outdoor burner for now and see if that works, because like someone else mentioned, I really need to get out of my parent's kitchen. I'll let you guys know how it goes. Thanks for the replies guys.

[morticaixavier]

Weird, I have never heard of anything like that!

it could be that the element is too small so there is too much hangin over the edges. do you have anything heat proof that you could use to support the edges of the pot?

Heh, well when it happened I sort of panicked and tried weighing the handles of the pan down with dumbbells....came close to a disaster haha.

If you mean could I wedge something under the sides of the pot, but wouldn't that not heat it up properly?

I might go for the outdoor burner for now and see if that works, because like someone else mentioned, I really need to get out of my parent's kitchen. I'll let you guys know how it goes. Thanks for the replies guys.

I was kind of thinking just enough to provide support to the edges without lifting the center of the ot off the element too much. but having brewed with a turkey frier type burner for the first time a couple of weeks ago I would say DO THAT. it's awesome to be able to bring 14 gallons to a full boil in 20 minutes! and it's so much nicer brewing outside with  soft breezes and the birds singing than in a dark, steamy kitchen. Plus I didn't get so tired from the hops that I wanted to take a nap half way through my brew day.

[richardt]

Metal expands when heated.  This could create irregularities on the bottom of the kettle.
It is also plausible that boiling water (or wort), could temporarily cause relatively asymmetric volumes (and weights) due to the creation of bubbles of steam that would displace the remainder of the water towards the other side of the pot.
Unless you've got a tri-clad, machined-smooth, kettle bottom, there's a good chance that it will qiver on the stove top. 
I have an aluminum pot with a rounded bottom edge that just rattles horribly when in full boil on the stove top.
OTOH, my tri-clad SS boil kettle does not rattle on the banjo burner during use.