There are a couple of different questions here.
Johnson Controls makes a line of "thermostat override" devices that can be used to modify the maximum temperature a unit can go to. Most refrigerators want to work in the range of 28-46F or thereabouts. Using one of these override devices you can set the max temp to 55F. By the way, one of the least expensive storage units you can buy is a chest freezer. These temp controls work perfectly for that application
That doesn't solve the humidity issue. One way to do that would be to use a product like PolarFresh or panels from Avive, which are placed in the compartment and reduce humidity.
The streaking you're seeing is probably because the chocolate you're using is unevenly tempered. For example, in a Chocovision machine, you need to wait a few minutes after the machine says you're in temper to evenly distribute the desirable crystals to influence even crystallization. Without knowing more, I'd say you need to mix/agitate your chocolate more than you're doing once it's "in temper."
Why and how are chest freezers the least expensive? I would like to know more about this. Chest freezers are probably the easiest thing I have access to obtain, but I would think the moisture condensation would be too much of a problem. I live on an island in SE Alaska and while temperatures are not the problem, humidity and obtainability are problems.
Thanks in advance,
Chest freezers are available through many retail outlets and tend to be very inexpensive compared with specialty refrigeration made for working with chocolate.
They do need to be modified to work for the purpose of storing chocolate:
a) You need to get a thermostat override device like the one from Johnson Controls. While you might get a 7 cu/ft chest freezer for $300 (here in NY), the controller might cost another $70. This is still inexpensive compared with $5,000 to $10,000 or more for specialty refrigeration. You wouldn't use the chest freezer for crystallization, only for storage.
b) You need to add something into the chest freezer compartment to control humidity. One option is PolarFresh; it works like a box of baking soda but it's specifically designed to help control humidity; baking soda is only about controlling odors. There are other options - but as you say, obtainability is the issue.
When putting things into the chest for storage, you'll want to pack them in a way that protects them from exposure to air and humidity. You don't want any humidity to condense on the items when cooling down or warming up. SO ... the best way is not to use huge tubs that need to be opened and closed, exposing all of the contents to the air each time the tub is opened. You could do that for organization purposes, but then I'd wrap "serving size" portions individually and put those into the larger tubs. Opening up the tub would then not expose unwrapped pieces to the air.
When taking items out of storage, you have to let them warm up to ambient temperature before unwrapping them to keep moisture from condensing on the chocolate ... it will condense (if present) on the outer wrapping.
OK, that makes sense. I already use "serving size" portions when I freeze items now. I couldn't figure out how a chest freezer would work for crystalization. But from what I'm reading the override device from Johnson Controls would also work on refrigerators, correct? I regularly use a dehumidifier for the ambient air, but I'm still struggling with the crystalization problem - small kitchen spaces don't allow for the unheated room I used at home!
Yes, the Johnson Controls device should work with most refrigerators to get the temp up to 55F or so, which is usually above their range. You may want some sort of commercial fridge because it will have the wire shelves you need - home fridges are not set up for this.
If humidity is still a problem, try one of the PolarFresh units, and you might even consider a very small computer fan on a dimmer to increase air flow.
thank you, I'm going to try that!