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If you make yeast starters, our heat-resistant glass Erlenmeyer flasks are perfect for preparing the starter solution and growing the yeast. Put the bottle directly on your stove to boil and then cool (with the bottle sealed with a foam stopper) before adding yeast to minimize the chance of infection. Withstands temperatures of over 700 F.
This 2000 ML bottle fits our Q38 Foam Stopper. We do not have a rubber stopper that fits this, but the Q38 acts as both a stopper and bacteria filtering airlock.
A gas stove is recommended, as electric burners can cause the glass to crack. Approx. 11" tall. These are general laboratory grade, and may have small bubbles in the glass or other imperfections that will not affect use.
This flask has a pronounced concave bottom and will not work with my magnetic stir plate. There is nothing in the product description suggesting that its anything but a standard, flat-bottom Erlenmeyer. Buyer beware, don't throw away your packing material until you are sure it works with your equipment.
William's Brewing Responds: This is defective. Please contact customer service at firstname.lastname@example.org or 800-759-6025 and we will get you a flat bottomed flask. Thanks.
Based on another review I expected this flask to have a flat bottom. Mine does not, it has a concave bottom that is causing my stir bar to be thrown occasionaly. When I called Customer Support I was informed that these flasks are made in China and he couldn't guarantee me a flat bottomed flask. So I will return it and source a true Pyrex flask from another source for the $2 dollars more. Shipping was lighting fast though.
Response from William's:
All the flasks we in stock have a very slight (barely noticeable) dip up in the center of the flask which appears to be part of the design. We have sold hundreds and not had a complaint, and many of our customers use stir plates. Please return this to us, filling out the back of your receipt. Be sure to write how much you paid for return shipping and we will reimburse you for this. We need it back because we are not sure if you have one like all the rest, or one with a bottom that is defective. Thanks!
This particular yeast bottle has a internal flat bottom that keeps my magnet from being thrown off center when using my stir plate. The other flask I own is concaved internally on the bottom which allows my magnet to be thrown off center.
Pros: Excellent size and workmanship. Keep in mind that these things are hand-blown -but they're exactly as advertised. I ordered two of them, put them right on the stove and boiled the starter wort, put them in the sink for an icewater bath, no issues whatsoever. They take #10 bungs (I don't use the foam ones, but standard rubber/airlock combo). These are shipped very well protected.
Couldn't be happier! Cons: None whatsoever. Exactly what I expected to get.
Pros: This flask allows me to do a larger starter. I am able to go directly from the stove at boiling temps to a cold water bath. Cons: Some small streaks and bubbles in the glass, all at the top.