Hi Tom. There's no date on the bottle so the shelf life is unclear. That little bottle would last for years if the solution doesn't degrade since you only use a few drops in the probe cap and once in the cap the solution doesn't really go anywhere. Any excess that gets pushed out of the cap will crystallize but the stuff residing in the cap sponge will remain a liquid. I've had a bottle for year now and it has small bits of what looks like mold in it so I suspect it may have perished. It's almost completely full and I've only opened it twice to replenish the probe cap. That being said even if it only lasts a year it's worth it to keep the probe healthy. The probes cost much more than a bottle of this. I've found out adjusting the wort/must/wash acidity is the single most important influence on the yeast. The Beverage Dr. tester makes that possible. To me the tester is as crucial a tool as a hydrometer.

Before the COVID-19 interrupted our life I brewed twice a month. Now brew days are not so frequent. Not because of time I have a lot of that on my hands but because my brew buddy can't come over as often and I donated my second fermenter (freezer) to storage for food. So I always used about 4 drops each time I put my meter up between brew days. The small bottle of storage liquid should last about 10 to 15 brew sessions. Now this depends on how long the meter sets. If you have a perfect seal it should last a couple weeks. You need to check on the meter to make sure it hasn't dried out. I hope this helps. The storage liquid in the bottle should last a very long time if kept sealed at room temperature.

You only need a small amount at a time to keep the bulb wet so a bottle should last for at least several years. If the bottle is kept tightly closed it should last almost indefinitely.

It's enough for a couple changes. I order my storage solution and calibration buffers from Hannah Instruments. I keep my storage solution refrigerated which should extend the shelf life. Which I think is a year or so at room temp.

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