Erlenmeyer 5L - lump on bottom - experience in getting stirbar to spin

[RagingBull]

Afternoon brewers,

I'd recently purchased a 5L Erlenmeyer flask (with wide mouth) from a science for kids type online shop - due to it being the cheapest one I could source on the net and also confirming by prior email that it had a flat bottom.. This may be one for the adage: buy cheap buy twice...

I was keen to get the flask out and give it a test run - then immediately noticed it had a Ø10mm x 3mm hemisphere pointing upward in the centre of the bottom of the flask; naturally affecting the central placement of the 25mm oval shaped stir bar I possess.

I'm hoping the ahb community may have some remedial advice on any of the following.

Worst-case I can just return and source elsewhere, but if there is a solution I'd be keen to try.

- Do your own 5L flasks have the same issue on the bottom? If so - do you position your stirplate away from it with success?
- I've read the bar-bell type stir bars may be a solution? anyone here had success?
- Get stronger magnets to hold it down in the middle
- Should the above not work - Any other ideas?

Cheers,

edit: "- Get stronger magnets to hold it down in the middle"

 

[Truman42]

Keep it for rinsing yeast from slurry and buy a new one.

Or if your stepping up to a 5 litre starter from smaller ones don't worry about putting this on the stir plate. Just give it a shake every now and again until fermentation starts.
That's what I do.

 

[TidalPete]

It might help others if you can give a link to where you purchased the erlenmeyer from?

Can you get a refund? It could well be just a production hiccup.

A bump of that magnitude in the centre of the base will most certainly cruel any chances you have of using a normal stirbar.

I have stirbars of various lengths including a bar-bell type (50mm) which turned out to be a disappointment when used in erlenmeyers of over 1000ml so now it's only used to stir Polyclar in my 500ml flask but that could possibly be attributed to the distance apart of my magnets (50mm) on the fan?

If I was doing this again I would get a nice, long, rectangular rare-earth magnet that weren't available when I made my stirplate.

It's not the end of the world if you (Like me) don't want to spend big bucks on a decent 5-litre jobby. Anything around the same size (wide neck or not) will suffice as long as the bottom is flat.
I recently said goodbye to my trusty 4.0-litre lolly jar from the old Burleigh Heads Picture Theatre. So old that it broke up when slipping from my hands in the sink. :mellow:
Casting my eyes around for something cheap & easy as I type.

 

[ian_2005]

There are a load of cheap earth magnets on ebay

i would recommend the bigger ones

Here is an example http://www.ebay.com.au/itm/1pcs-20mm-x-3mm-Disc-Rare-Earth-Neodymium-Super-strong-Magnets-N35-Craft-Models-/270879304043?pt=AU_Miniatures&hash=item3f11aa296b

Not sure about the size of the one i used but its rectangular from memory

Worth a shot

 

[Yob]

I found that my 25mm bar kept on throwing itself, some shorter ones suited my plate and does the job well, caviat being that I generally dont need bigger that 2lt.

I rekon that if I was having trouble ATM I'd just get one of those flash Digital Stir Plate mo fo's :beerbang: and go from there.. that said, what stirplate do you have? are you sure it's the flask?

Im actually wondering why I aint future prrofing as it is h34r:

@truman : Why do you need a stirplate for rinsing yeast? :blink:

 

[RagingBull]

Cheers for the replies gents.

I'll sleep on it whether I return it or not. Utilising it for other uses round the brewery is a good point.

Albeit given I'd confirmed the flat bottom and received quite the opposite, the group (madabout science) has been quite responsive and obliging re: returning the item since it was sent as an e-parcel (they can cover the return costs). They've also advised me to source elsewhere upon return since it was the only one they had in stock.

http://www.madaboutscience.com.au/store/5000ml-glass-erlenmeyer-flask-wide-mouth-p-625.html

A bit of inconvenience, but no worse off.

Thanks for the swift and productive response.

 

[RagingBull]

Yob, just saw your post. I have been wondering if stronger magnets would hold the bar. I might consider that and duck to a local retailer (as my magnets on the TASP are cheap ebay ones) and give it a go prior to return.

I figure having the right tools for the job is a big factor, and a flat bottomed flask (which i assume most of you have - and my smaller flask is) is the right way to go.

 

[Yob]

na mate, I got slightly domed flasks... my stirbars have the little ridge in the centre. The 'tinkle' and annoy the shit out of SWMBO during winter :lol:

I run mine at 3/4 speed as a compomise as vortex to the bottom never worried me and I dont acheive it with the rig I have anyway.. but hay, it deos it's job.. but only just... when something like linked above is availble, Im sorely tempted to get amoungst it.

Not sure if stirbar tests were done with it and I guess thats a question for the other thread, size, types (barbell v's centre) etc

:icon_cheers:

 

[Truman42]

@ Yob... I didn't mean to use the stir plate to rinse yeast. I meant use the flask as a vessel for pouring the slurry into in order to rinse the yeast.

 

[Yob]

Roger Roger, just the way I read it... sorry, a bit bleary eyed right now

 

[Wolfy]

If it's a 5L flask you might find that it is flat a bit away from the center, try positioning the flask so the stir-bar is not in the center, if it spins it will work just as well.