Looking for cellar/wine fridge nerds... will my wine fridge conditions affect my wines' aging? (temp log/graph within!)

Hi all -

I took the plunge on a massive Wine Enthusiast fridge (holds supposedly 300 bottles, I have right at 250 in there including 13 magnums and a double mag, 3 500mL and 5 375mL bottles; has a charcoal filter that purportedly controls humidity) a few months ago. I have had a temperature and humidity logger for a number of years and I decided to see how well the wine fridge holds its temperature and humidity. I am hoping that some really hardcore (or even academically qualified!) cellar nerds can comment on what I am seeing here and how it might affect the way my wines age. My hope is that this is nearly as good as having a passive underground cellar insofar as ability to age wines properly and well, although the character and frequency of temperature fluctuations will undoubtedly be different from those within a passive underground cellar. I am not considering vibration or light when testing here.

I set my logger to check temps and humidity every 10 minutes (or 5, can’t remember which, it really is no matter) and graphed it below. The fridge was set at 52 degrees Fahrenheit. The fridge has 9 shelves where bottles can be stacked 2 high, plus a bottom section that I use for magnums (and a 3L) that can stack about 3 high and a top shelf that can hold about 2 champagne or larger 750mL bottles stacked. The fridge runs 2 bottles deep from front to back when packed with wine.

My logger was set in the middle of the middle shelf, not in physical contact with any bottles but rather nearly touching the top tips of 4 bottles it sat between. I live in South Carolina and away from the coast but still in a relatively humid area.

Here is what I can glean from the log:

• The cooling unit comes on when it hits 55F in the middle of the fridge.
• The cooling unit turns off when it hits 46F in the middle of the fridge.
• The cooling unit comes on about once every 27 hours and runs for about 4 hours each time in a room that is typically around 72-75F.
• The average fridge temp is approximately 51F; the fridge holds its temp in degrees Fahrenheit longer the closer it approaches to room temp, making this calculation a bit more difficult.
• While the fans within are running, the logger shows an acute decrease in ambient air temperature, appearing to drop 11 degrees in 2 hours and then an additional 5 degrees in 2 hours. I realize that the actual wine bottles (made of glass plus the liquid inside) are not fluctuating nearly that much and are, in fact, dropping from 55F to 46F over a 4 hour course. This is a 2.25 degree Fahrenheit drop per hour on average over 4 hours. I imagine that would be a bit faster drop for the bottles in the back near the cooling fans/cooling wall, and a bit slower for the bottles in the front nearer to the door and away from the cooling components.
• During idle time there is an increase of about 0.33F per hour over the following 27 hours. This speaks to both the insulation of the unit and the ability of 250 bottles to maintain a steady temp about 17-30 degrees below room temp.
  -Humidity runs from 65-68% during idle time (27 of every 31 hrs) and drops to the mid-50’s while the unit is actively cooling (4 of every 31 hrs)

My next projects will likely be:

• Logging temperature/humidity in the bottom section and the top shelf and perhaps right and left edges of my fridge, and the frontmost and rearmost areas, trying to keep the logger away from the fans’ direct line of fire, to see if the actual temps in those sections fluctuate more or get away from goal temp more.
• Getting some simple general differences between those areas and the dead center of the fridge that I just logged at. Future logging sessions will likely have the meter sitting wedged between the body of two bottles of wine so as to decrease the wild fluctuations I saw here with the logger being between the tops of the necks of some bottles where the most air would move and the least influence of the bottles’ actual temperature would be.
• Checking similar tests in my under counter Sub-Zero dual zone wine fridge that holds about 60 bottles and the Haier fridge I bought about 12 years ago from Craigslist for 50 bucks which holds 50 bottles, 13 of which are 375mL bottles of Sauternes/Barsac wines. It has been running like a champ since I bought it which is impressive, costing me a little over 4 dollars per year outside of energy costs, or 8 cents per bottle per year .

If anyone has suggestions of other tests I should try with my two fridges that I am actually aging wines in - the Haier and the big one - I am up for giving it a try and making this a megathread about wine fridge conditions.

The bottom line for me is to figure out with your help whether the conditions in the big fridge I have are close to those of the tried and true Eurocave fridges that folks have that seem to age wines even long term without issues. Even better to compare to a walk in cellar with a cooling unit. If the fridge is not close to those conditions, wondering how my fridge’s conditions may affect my wines’ aging. The only thing I am tempted to do right now is to up the temp in the fridge to 55F, but want more data before doing much of anything.

I welcome any thoughts you guys have here. I have posted this in the cellartracker forums as well.

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If interested in seeing it, the cellar itself looks somewhat similar to this, though only the central 4 shelves have the vinoview feature and the rest just show the punts of the bottles facing the door: Classic XL 300-Bottle Wine Cellar with VinoView Shelving - Wine Enthusiast

It’s odd that your cooling unit only kicks on every 27 hours and then runs for 4 hours! Most of mine kick on every hour and run for about 5 minutes. Can you adjust the temperature set points on your cooling unit?

Air temp is useless. Get a liquid thermometer in a used wine bottle filled with water. Then get samples every 10 minutes or 2 hours or whatever.

I am all for getting a liquid thermometer to put in a used wine bottle for logging, so long as I can somewhat readily interface it with my computer and create temp logs with it. Do you have any suggestions for me to purchase? In any case, my ambient air readings can at least provide humidity data and data on active cooling times.

You’re worrying about differences in air temperature far too much. As long as the liquid stays within a few degrees, there won’t be a problem at all.

Agree that monitoring bottle temp will tell you more. What this air temp graph tells you is that the unit is working well, and there is a lot of thermal mass to cool down, probably just a few degrees each time.

Given the stability of your chart, you don’t need to log the bottle temp. Get a bottle probe, and just look at it, say, an hour after the unit kicks off, and just after it kicks on. That will tell you what the temperature range is inside the bottle.

But looking at your chart, it seems very normal, and looks like everything is working perfectly. My guess is that when you measure the liquid temp in a bottle, you’ll see a range of about 48-54, which is just fine, maybe even too cold.

Didnt have time to read the entire OP but is the logger an accurate one? I would have started there first then analyze the data.

same here

Have had a passive cellar for 30+years.
52-62 winter to summer never goes above
65 humidity. Point being wine is more resilient
than most of us think.If you want to geek out
about it after all it’s your wine, so have at it.

I’ve been using Wireless Tag for this - not expensive and shows what you need to know. https://goo.gl/QLemY8

+1 on this set up.

My view: In reality, almost certainly not as air temp will be much wilder than bottle/liquid temps. I use “Temp Stick” to monitor my wine fridge but mostly as an “alarm” in the event it starts to freeze over and/or stops working (I have it alarm below 45 or above 65).

However … if you have “investment grade” wine (GC burg, class growths, Screagle/Harlan, etc), there is value in your wine being “professionally stored” in the event you want to sell it.

My thought is your thermostat in the fridge is a cheap one that does not cycle on or off quickly enough. A good thermostat will cycle with a 2-4 degree air temp swing. This will cause the unit to run more often for less time, with more constant temperature. But you really need an in-bottle probe that not just measures the temp, but controls the cycle of the unit itself. These have much more sensitive thermostats, since the liquid doesn’t vary much more than a few tenths of a degree. Think sous vide machines that have a PID that keeps the water bath at +/- .1 degree.

And a charcoal filter has nothing to do with controlling humidity.

Wineguardian recommended against bottle probes for maintaining temp.

Agree - liquid temps change too slowly to cycle the cooling appropriately.

Really the unit should be cycling to maintain air temperature within a much narrower window than this one does - not sure if there’s an industry standard tolerance but my window unit+Coolbot keeps the recorded air temperature within a 1 degree band over the entire year, and within about .3 degrees on a daily basis (it might vary a bit more if I’m in the cellar for a while).

If you want to know what temp swing your bottles are seeing, as others have suggested and is really what matters, put your sensor through a cork into a bottle filled with water.

IMO your 9 degree dead band is way too large, you can tell from your graph, it cools down relatively quickly then has to run because…the bottles have gained temp and they need to be re-cooled.

Google your unit and see if the dead band is adjustable, and if you can’t tell call the manufacturer.

FWIW I can adjust mine in 1 degree increments and use a 3 degree dead band.