how can I refuse a comment like that especially from Shel.
KYH, you precisions are well placed but an upright (even not frost free) has more temperature swings just because the cold air basically pours out of it when opened and once closed required additional work to bring down the temp. What temp variations do is change the amount of water vapour the frozen food will let go due to the temporary <warmth> in the freezer hence the meat will dry slightly everytime. Overtime snow will appear. Again, a chest minimizes this affect because the cold air stays put.
I tried vacuuming and submerged the bag to air out. The results do not differ that much from what I do now. I have kept many meats for months to a year without burns (snow yes but not burns). The snow appears mainly because I open and close resealable bags taking what I need only and leaving the rest in the freezer. This action changes the water vapour considerably in the bag.
I guess if you have a vacuum gadget around the house, use it but I caution to vacuuming extensively frozen food because that also changes the water vapour pressure dynamics (sometimes increasingly). The best thing to do, I found is to adhere wax paper on the cut sides on the meat while its fresh. once frozen that prevents some surface to vent water vapour while frozen but I abandoned that because I have seen minor improvements.
A cool topic
From the icebox to today’s stainless steel behemoths, we have increased our dependence on refrigeration, a boon for food storage. For the <domestic food provider>, that’s my job at home, knowing how a refrigerator works is useful information to properly use this essential kitchen appliance effectively.
We all know the term <freezer burn> or witnessed at least once, a forgotten frozen something with a tear in the wrapping that appeared to have dried beyond recognition. Storage bags and vacuum packing machine manufacturers tell us their products can avoid <the burn>. They work somewhat but do not address the real problem: the physics behind the refrigerator. In my childhood, a freezer was a small metal box with a door surrounded by a cooling coil fasten to the ceiling inside the actual refrigerator. A refrigeration coil basically draws heat, not air, from the interior of the refrigerator to exhaust it outside. Physics states that cold air is denser hence heavier then warm air. By placing the freezer box above, warm air rises to it, cools then falls back down to refrigerate the entire space. Open the door and all the cold air pours out. Physics also explains that warm air holds more moister, water vapour, then cold air. This means that as the coils draw the heat from the air, the water vapour escapes the cooling air by condensation then freezes. Overtime, a thick ice sheet accumulates on the coils. I have childhood memories of my Mother defrosting the refrigerator: unplug the appliance, open the door and let the ice melt.
Although the mechanism of frost free refrigerators of today works on the same principle, they solved this ice build up inconvenience by cycling the temperature of the freezer compartment periodically using modern electronics. Once and a while the freezer temperature goes above freezing so that any accumulated ice melts away, down a drain, to never accumulate. This cycling has the cumulative effect of drying the air hence dehydrating everything in the refrigerator. Overtime this effect causes the dreaded freezer burn of improperly sealed food. In the case of sealed frozen food, the temperature cycling coaxes a little food surface ice to evaporate, which then refreezes in the surrounding sealed air pocket explaining why snow crystals accumulates inside the bag. Storage bags may prevent <the burn> but not the snow and vacuuming may worsen this affect. Note that the refrigerator dehydration worsens the harder the appliance works like during summer.
Next week: What to do? freezing and refrigeration tips.
Another cool topic
Today’s frost free refrigerators dehydrate everything stored in it. Here are some generic tips to cope with this flaw.
Because fresh fruits and vegetables are plant materials that contain water on a cellular level refrigerating them is tricky. Plant tissue is like a sealed garbage bag filled with 100 water filled balloons. If the balloons are filled really big and firm with water, the garbage bag will be sturdy. If the balloons have less water, the garbage bag will be limp. Over time, fresh fruits and vegetables get limp in the refrigerator because their cells, analog to balloons, lose their water by evaporation. Here are some refrigeration tricks I developed by observations and research over the years. The following foods need to be washed, rinsed and dried then sealed in a bag or container: Leafy greens like lettuce, chard, spinach. For broccoli, cut ½ inch (1-2 cm) off the foot. Let it stand upright in cold water like a flower bouquet for about 1 hour. If it was a little limp, it will firm up. The same technique applies for celery but cut off both top and foot.
Small fruits like grapes, strawberries, boysenberries, blueberries should be washed only prior to eating but must be sealed to refrigerate. Root vegetables do better in a cool, dry and dark place but not everybody has a root cellar. You can store unwashed rutabagas, carrots, celeriac and parsnips but not potatoes. Refrigeration causes cold induce sweetening and softening of potatoes.
Citrus fruits with their thick skins and apples resist dehydration well so they do not require to be sealed. Ripening fruits like pears, peaches, bananas and even tomatoes fair better on the counter then the refrigerator. They do not store well for extended periods so plan to consume them within a week. Forget raspberries and eat them as soon as possible.
Because of the defrost cycle of upright modern refrigerators, storing frozen foods should be considered only for short periods. For prolong storage, one should consider a chest freezer. They constantly maintain a freezing temperature. The chest configuration also prevents losing all the cold air when open unlike an upright. The cold air stays put because it’s heavier then warm air hence freezer burn and snow are kept to a minimal. To avoid storage temperature swings, freeze your food in the refrigerator freezer first then transfer it to the chest. Well sealed frozen food can be kept for months. Ice cream stores better in a chest freezer.
I did not answer a question you have? Just ask me.
Luc H offers home cooking, family nutrition and basic food science classes in and around Montreal.
I eat science everyday, do you?
I eat science everyday, do you?