Buy “Hanna Instruments HI 190M-1 Magnetic Mini-Stirrer with Speedsafe, 110/115 V Power Supply Science Lab Stirrers Industrial & Scientific” Online
The Hanna magnetic stirrer is a hobby-level piece of equipment that does what one would expect. It stirs. I use mine to make simple syrup for my bar and hummingbird nectar for the feeders. Typically I mix from 500 to 1000 ml of fairly dilute sugar in water. I believe the Hanna stirrer is meant to be used with a 25mm (1 inch) stir bar, but I have used 50mm bars with no trouble in a dilute (non-viscous) water solution. That said, I should point out three limitations, but, at the price point, I think they are fair limitations. First, the rheostat (speed) control is not a true power off switch. Yes, it controls stirrer speed, and there is a detent click "off," but listen carefully, and, while the stir bar stops, a motor continues to run when the switch is turned to "off. " The power on light continues to glow as long as the stirrer is plugged in. Look in the manual, and the instructions say to pull the power plug if you won’t use the stirrer for a while. Second, there is no protection for the rheostat (speed knob) if liquid should spill. The illustration shows a standard Griffin (open) beaker. I prefer Erlenmeyer flasks for their narrow openings. Less evaporation as well. Third, the rheostat / speed knob is recessed under the top lip, and, unless your fingers are tiny, it takes some attention to adjust the speed or to turn the unit on and off. If you’re willing to live with the inconveniences, especially of unplugging when not in use, the unit appears robust and should save you some money if all you do is stir up sugar water to feed yourself and the hummers. However, . ..If you’re willing to spend approximately double the price, order the Scilogex 86143101 Model MS-H280-Pro (also from Amazon). It’s a much more robust stirrer, it includes a hot plate, both functions have digital displays (stir speed and temperature), and it has a true on-off switch. It’s what you might expect to find in a working lab. Check it out!
The Hanna Instruments HI 190M-1 is a magnetic mini stirrer that comes with a magnetic mini-stir bar, and has an internal Speedsafe control mechanism to assure maximum speed of no more than 1,000 revolutions per minute (rpm), even when the sample container is removed. Speed range of the unit is 100 to 1,000 rpm, and maximum stirring capacity is 1 liter (.26 gallons). The device comes with a plastic, chemical-resistant acrylonitrile butadiene styrene (ABS) cover, and works with a 110/115V power supply. Overall dimensions are 45 x 120 x 120 mm/1.8 x 4.8 x 4.8 inches (H x W x D). The stir bar is 25 x 7 mm/ 0.98 x 0.28 inches (L x W), and the instrument weighs 640g (1.4 lb.). The stirrer comes with a one-year limited warranty. This magnetic stirrer is used by researchers, professionals, and hobbyists to stir a variety of liquids and solutions in chemistry, food and beverage, pulp and paper, lab, and home applications. Researchers, professionals and hobbyists use a magnetic mini stirrer to stir a variety of liquids and solutions in chemistry, food and beverage, pulp and paper, lab, and home applications. Magnetic stirrers have a rotating magnetic field that causes a stir bar, immersed in liquid, to spin and stir the liquid. A magnetic stirrer is quieter, and more efficient than a motorized stirrer, and has no moving external parts that could break or wear out. Because of its small size, a stirring bar is more easily cleaned and sterilized than manual stirring devices, and does not require lubricants which can contaminate the reaction vessel and the product. Hanna Instruments manufactures analytical instrumentation and supplies, including pH meters, electrodes, chemical reagents, and buffer solutions. The company, founded in 1978 and headquartered in Woonsocket, RI, meets International Organization for Standardization (ISO) 9001 standards.
Hanna Instruments HI 190M-1 Magnetic Mini-Stirrer with Speedsafe, 110/115 V Power Supply Review
Purchased this with a 5L flask to make big yeast starters for 10gal batches of beer. I was a little concerned when I opened the box and read in the instructions that the maximum stir capacity is 1L. So I filled the flask with 4L of clean water to test it, and the stirrer created a nice vortex that intermittently touches the bottom of the flask at maximum speed, and it never threw the bar (it comes with one bar) once in about 15 mins of operation. Perhaps with a smaller volume of liquid it would keep the bottom of the vortex on the bottom of the flask permanently, but I’ve read that it’s only really necessary to have the surface of the starter moving to promote gas exchange which means a vortex is overkill. Since a 4L starter is probably the maximum I’ll ever do, I’m happy with it. I hope to get the same performance with a starter which is denser and more viscous than plain water. Will find out this coming week. Oh, and a 5L flask is more than stable enough on it. Can’t testify to the longevity of the product, but at this relatively low price, I believe it’s a fair trade. -Read Reviews-
I purchased this in January 2017. It has been in almost daily use since then. I use a 1,000ML beakers and have run batches of around 600ML. I like the fact that it is not heated as I work with cold solutions. It cleans up easy from spills and I have had no issues with it as far as performance goes. If you read the directions it has some features like stopping when the stirring magnet is removed. It is quiet.