I've long suspected that my controllers may not be accurate. Professional calibration is inconvenient and expensive, while the salt method is not reliable enough to instill confidence. I've generally been happy with my salumi, but am I getting the best results I can? However, I check my meats periodically and adjust humidity up or down depending on how the skin feels. It's never been a 'set it and forget it' process.
I've also experienced a few puzzling situations where I had no idea how they could possibly happen. So, I decided to invest in a professionally calibrated reference hygrometer. My choice landed on Hanna Thermohygrometer HI9565, which I purchased from their website. I've had a couple of Hanna PH meters for many years, and they've been exceptionally accurate and reliable. I hope the hygrometer shows the same level of accuracy and longevity. So far, I've been delighted with it. It has a 0 -100% range (very few of them do), high accuracy (±2.5 %), and is quite responsive. Was it worth it? Absolutely! Here is why:
I've been asked dozens of times about Inkbird vs Auber controllers. Are Auber controllers better? A while ago, I bought Inkbird ITC-308 and Inkbird IHC-200 temperature and humidity controllers with the intention to play with them and do a detailed review, but life had other plans for me. At some point, I used them with one small batch and they did the job. Then, while I was testing my Auber controllers against the Hanna HI9565, I decided to throw the Inkbirds into the mix. How did they do?
Out of the box, both Auber and Inkbird RH deviated from the reference Hanna hygrometer by 9.5 percentage points (Inkbird) and 3.7-4.3 (Auber). This was when measuring RH in the fridge at 56F, after a 30-minute stabilization period.
When testing outside of the fridge at room (basement) temperature of 68F, again after a 30-minute stabilization period, Inkbird was off by only 3.2 percentage points, while Auber was off by 6.7.
Here is another test under the same conditions as before, but Auber had a brand new sensor. Again, the Inkbird was the closest, off by only 3.4 units, while Auber was off by 7.2. Note how the temperature reported by Inkbird is spot on, while Auber is off by almost 2 degrees.
Auber controllers seem to be optimized for the curing temperatures of around 55F, while Inkbird seems to be more accurate at higher temps and vice versa. Both Auber and Inkbird humidity controllers are not perfect and need to be calibrated. The deviations that they show are significant enough to cause major impact on curing results.
If you calibrated them at 55F, will they still be accurate at 70F-80F during fermentation? This is where a reference hygrometer like Hanna becomes invaluable.