I bought one last year. It regulates the temp. They are used by wine guys i think... I haven't tried mine yet, since i ended up with a total of i think 3 apples :) Its made by Johnson Controls, model A19AAT...

You find stuff like that at brew shops.
Don't forget the extremely high humidity.

Here is a link that might be useful: http://www.midwestsupplies.com/homebrewing-equipment/fermentation-equipment/temperature-control.html

Yes, humidity, good point. Modern frostless refrigerators are extremely dry inside. Not suitable for apple storage I would think. Incidentally, I'm currently digging a "root cellar" to store my apples, beets, carrots and whatnot. I sure hope it works.

"Modern frostless refrigerators are extremely dry inside"

That's what makes these controllers so great. I don't think any chest freezers are frostless.

I'm not sure I am following. Chest freezers are high in humidity compared to upright or frost-free freezers? Humidity is desirable in apple storage? Please explain.

YES..high humidity is what you want, along with temps near freezing. I think 33F or 34F...dig around for the exacts. Refrigerators blow for this purpose. I use an old small chest freezer that i broke (still works fine, just hinges are bad)...

Root cellar? I thought about that but the ground temp is so warm around here this time of year. Almost need to be cooled with well water or something. Just for example, right now the ground temp at 5ft (according to the NWS) is 60F.

If you have frostfree refrigeration, store in plastic bags with some small holes.
Root cellars work well for some of the better storage varieties, like Gold Rush, Pink Lady and Ark Black- especially if you want to "age" them a bit- the process of having some starch convert to sugar. The down side is they tend to be too humid, encouraging summer fungus to continue growth and of course the lack of temp consistancy.

Not all apples necessarily store best at the cusp of freezing or even a couple degrees below. Honeycrisp is supposed to store better at warmer temps, for example.

I was the one who posted this a while back. All you need is a freezer chest that doesn't have defrosting, and a thermostat controller that cuts the power when the temperature inside drops below a specified number. I use 34F on mine.

I've had amazing results with this techniques. My best storers have been pink lady (keeps forever) and zestar (a summer apple that was delicious even after 7 months of storage!) I've been able to get a number of sour-when-harvested apples to mellow in storage without degradation in texture. For example, Belle de boscoop, a cooking apple when first ripening turns into a delicious table apple by about December.

It's a bit of an art, though, and can be hit and miss. Apples that are great one year maybe terrible the next. This is true mostly with the heirlooms, less so with commercial varieties that seem to be bred to be rather consistent no matter what the growing conditions might have been.

I store my Galas, not known as good keepers, inside the jumbo ziplocks with the zip open an inch or so for ventilation. Last year they lasted til summer in the fridge.

tcstoehr, if you store the apples with the other stuff, the other stuff will turn to dust due to ethylene. Make a hole for the apples, and one for everything else.

Yeah, my hole-in-the-ground root cellar may turn out to be a bust. I don't know. It is generally too warm in October. My hope was to get root vegetables out of the garden and into storage before the hard November frosts hit. And for apples to store only the latest ripening ones left on the tree as long as possible.
I do have a couple of Goldrush trees and I have hopes for them for underground storeage. I think in the end there will be some successes and some failures.
I think humidity will be easily maintained but our mild PNW fall and winter temperatures may pose a challenge.

A picture of my "root cellar" for the bored and curious is provided below. Those are 2-by-eight boards I used. I have not yet fashioned a top cover.

tcstoehr-
that looks good. very nice craftsmanship. I hope it serves you well. Please keep us posted.

have you put a thermometer in the bottom to check it at different times of day? what are your low's (above ground) for this time of year? it looks like you have mostly silt-loam soil, correct?

I'm very interested to see how this works for you.

I see your wood is pressure treated, it might not be good, as some
of the chemical/fumes can escape. I was going with half concrete and
half wood on my cellar, now I build it all out of concrete.

I might try to build a root cellar someday, using a simplistic earthbag building process.

Regarding using pressure treated lumber for root cellar. Everyone has their own comfort level, but I would point out the new pressure treated lumber is much safer than the old copper chromium arsenate (CCA).

The main ingredient of the new stuff (for normal residential use) is plain old copper. Most pressure treated lumber also contains an SI fungicide which, unlike the old arsenate, have a very low toxicity to humans, and break down in the environment. Propiconazole is sometimes one of the SI's used. I spray it on my stone fruit. It has a zero PHI.

The new treated lumber is approved by the EPA for playground equipment, where kids grab and play on it all day long. I would think their exposure to the compounds would be much higher than any level from cross contamination in a root cellar.

I recently read an article that was posted on the organic gardening forum about using pressure treated wood to construct raised bed gardens. I'm not having luck finding it now using google.. but in conclusion it was acceptable.

It might be save to a degree, especially with the small sizes from Home depot. Still, you have to decide yourself, I can sleep better if not used, who knows, in another 20 years they might say that it's not safe...like with allot of other things. Around here you still can get the old arsenate wood for commercial usage, large sizes like 10x10 or 2x10 which I needed for my build, these larger sizes home depot didn't carry it. I was talking to one of the employee who is working there, he said that the new copper treated wood today doesn't last very long.
I wanted to build something what last for a long long time.
Konrad

I too would be a bit concerned about using PTW as a food storage container as I don't think they've been assesed for safety when used for this purpose.

There is a question in my mind about the volatility of the compound used and whether it might penetrate the apples in a closed system. This is much different than building raised beds.

This is just a layman's hunch as I have no specific knowledge of the chemistry of the chemicals used to preserve wood these days.

Again, I personally wouldn't be afraid of copper, borates, and propiconazole contaminating food, when they're all sprayed on food to begin with. But if someone was concerned about it they could always seal the inside surface of the treated wood with a paint or varnish. I good quality basement paint - the kind that seals out water - would probably stay on the longest.

Olpea, I'd be interested in your opinion on this.

This is the first thing that came up when I googled pressure treated wood and food storage.

"Do not use treated wood under circumstances where the preservative may become a component of food or animal feed. Examples of such sites would be use of mulch from recycled treated wood, cutting boards, counter tops, animal bedding, and structures or containers for storing animal feed or human food."

http://www.southernpine.com/pt07_userguide_storage.shtml

My take? In this case, the link you posted took it's information straight from the EPA safety information sheet for CCA lumber (see link below).

However, the EPA did not change the handling/building guidelines for the new lumber. It appears to me, barring any new testing, they simply rubber stamped the old precautions on the new wood.

It doesn't surprise me they did this. It's the easiest and safest route. But some of the guidelines leave one scratching his/her head.

For instance, we are advised to wear gloves when handling the wood, yet it's approved for children's playground equipment. Likewise, there are the standard pesticide precautions regarding clothing, but there seems to be a disconnect as to how that would apply to children coming in frequent contact with the wood on a playground.

I think it's as you mentioned earlier, new treated wood has not been assessed for food related uses. (No company is going to attempt EPA registration for this purpose because there's obviously no demand for it.) Doesn't mean it's unsafe, just that it hasn't been tested. Again, I'm talking here about the new wood. Of course one would not want to use the old arsenic product near food.

Here is a link that might be useful: EPA Safety Sheet for CCA Lumber

As I said before in different words, I have no background in chemistry whatsoever. Your logic is convincing but I'd still be inclined to use something else to store my apples, even if it is a superstition based cautiousness.

If I needed a quick easy root cellar I'd just bury a large trash can or other heavy pre-made container of plastic or metal (for rodents). You'd just need some kind of insulating blanket (as used by flower nurseries) or leaves to keep the ground from freezing up and to keep an insulating layer over the lid.

One of those heavy metal tool boxes on back of trucks would be perfect. The cheap alternative would be plastic storage containers- but you'd need to bait out rodents.

Axel- Thanks! I set up my freezer just the way you said to. It worked flawlessly. Apples were in great shape in April when we finished them off. Thanks again.

I'm going to assume that the apples will not be stored in direct contact with the pressure treated wood.

It would simply not be possible to build a root cellar with untreated wood. All that work would rot away in very short order, and the cellar would become dangerous as the wood lost the strength needed to hold the dirt back from collapsing.

In Portland, the carpenter ants and powder post beetles would have untreated wood eaten to sawdust in very short order.

The temperature of the earth, not all that far below the surface should be about 50 degrees, so I suspect that will be the on-going temperature in that root cellar, as long as the lid is well insulated.

It's not as good as cold storage, but it will sure beat having the fruit on the kitchen counter at 70 degrees.

Here is a link to my root cellar build I started this year, hopefully next
year it will be in operation.

Here is a link that might be useful: Root cellar into the side of a hill...

OWS, for what you're doing I'd use it also and paint it as Olpea suggests. You could also use something like cedar or redwood, I'd imagine, but that would be very pricey.

Thanks, Harvestman, but it's not me digging a root cellar. A cellar in my area would have to be dug out with a rock hammer and would probably cost 10's of thousands of dollars.

Instead, my son and I are carefully studying the possibility of installing a cooling room with a cool-bot.

Normally, fruit just goes into the garage, but this year, we've got apples and pears already and it's 80 degrees outside; too warm in the garage to hope for any delay in ripening.

Regarding the original question about using a thermostat to regulate a freezer to provide an optimal temperature for apple storage, I would think that if using simple equipment, this task would be more than it might appear. A simple thermostat of this type will shut off power to the compressor a few degrees below a set temperature and then turn it back on a few degrees above that temperature so that in theory the average temperature of the freezer is the set temperature. But what can happen is that when the temperature in the freezer hits the low that turns off the compressor, the system will then reach an equilibrium between the very cold coils and refrigerant in the evaporator and everything else, including the apples. This can bring the temperature well below what might be expected, especially if there is little fruit in the freezer. So if the thermometer is set for 34 degrees and the compressor shuts off at 31 degrees, the system may not reach equilibrium until the temperature reaches the mid 20's. While this may not ruin the fruit, I would wonder whether cycling fruit from the mid 20's to the mid 30's several times daily over months would really be optimal for fruit preservation.
Approaches to this problem would include using a thermostat that allows setting a narrower temperature range and keeping the freezer full.

Creekweb, where you place the thermostat is important. It has to be in a spot where the temperature of the coils themselves is being monitored. If you were to bury it in the middle of a pile of closely packed, bagged apples the compressor would run until the middle apples were the right temperature, by which time the outer apples would be frozen. It will take a few days for the mass of apples to reach equilibrium unless they are pre-chilled. If one puts in bags of apples a over a few days instead of all at once there's not likely to be a problem. (Thermal inertia rocks!)

I had a problem with apples along the edges of my little freezer getting too cold. A buffer zone (styrofoam, not cardboard) prevents that.

Good luck,

M

I agree; the placement of the thermostat probe can be a tricky business and a potential pitfall. Too close to the coils and it will be within a steep temperature gradient and give falsely low readings (as representative of the system); embedded within the apples, it will, as you say, be insulated from immediate changes in temperature that are affecting the outermost apples, cooling them far below what was desired before triggering the compressor off. There are going to be temperature gradients throughout the system, but I think a good strategy would be to avoid the area immediately adjacent to the sides, where temperatures are likely to damage the fruit anyway and then monitor the next coldest place, an inch or two from the side in an open area.

Some thoughts on root cellars.

First, root cellars have always required some manual management. People would open the vents/doors on cool autumn nights and close them during the days to bring the cellar temps down before harvest. The ventilation also required tinkering with to regulate the temps. You needed to close it off on especially cold spells, and adjust it other times as the outside temps changed.

So if you are just waiting for your cellar (or ground box) to get cold enough on its own, you will probably not like the timing. You need to be actively exposing it to cold nite temps before the food goes in. I suspect this was something folks just "knew" how to do as the older generations taught the young the schedule that worked in their location.

In terms of materials for a ground box, I have used a non-working chest freezer. Buried it up to the bottom of the lid. Metal and plastic inside, so no material worries, easy access, and some insulation. In my area it worked OK up til Xmas or so most years, then it would start freezing. Probably needed a pile of leaves or straw over the top.