Review on Hanna HI 98107 Precision Instrument by Ryan Brunson

This meter is much better designed than the competition (see also my review of the pH600AQ pH tester from Milwaukee Instruments). The ergonomics are much better. It has a switch that can be set to read continuously and calibration screws on the side. This allows you to hold the instrument with one hand and make adjustments from the side while constantly reading the display. This makes calibration easy and accurate. The meter has two calibration points at 4 and 7. I use this meter to measure pH during mashing. I use the Bru'n Water[.] chart to predict pH because most mashing happens very quickly, making subsequent adjustments less useful (although I still puree for an hour and then rinse very slowly). I measured several batches and noticed that the darker malts have a slightly lower pH than expected and the lighter malts have a slightly higher pH. Based on that experience, I found that I was now reaching my target mash pH, usually in the +/- 0.1 range, but no more than 0.2, and that's good enough. I don't need to measure pH for every batch, but I do every few months and when I change my process. What you can expect from any meter in this price range: 1) You have to buy calibration solutions which cost 8 to 10 8 ounce bottles. I use about an ounce at a time for sizing and have found that once a month is often enough. I pour that ounce from battle, calibrate, and then pour the solution into a second bottle (an old, thoroughly washed spice bottle is fine) for reuse, then use it 3 or 4 times before throwing it out and using a fresh solution. While I wouldn't recommend this for mission-critical applications, it works well enough for my needs. Be sure to think about how careful you need to be with your application. Before calibrating, I rinse the device thoroughly with reverse osmosis water and shake off excess water. With such a careful approach, I can take a few years off the bottle. 2) The pH sensor only lasts about a year. You can replace the sensor, but replacing sensors costs about the same as replacing a meter. Be careful when storing the meter with a pH probe, wet storage solution, 7.0 calibration solution, or reverse osmosis water. The sensor may stop working if it is dried. So be careful. 3) My first gauge didn't calibrate, seems to be a common problem. However, the exchange was very quick and easy through Revain. My second blood glucose meter has now been stable for 8 months. This gauge met my needs and helped set up my process.