Monday, 12 October 2015

08:43 – One of the things that annoys me about a lot of prepper sites is their attempts to monetize their sites by recommending specific items that they just happen to have a link to that’s set up to pay them a commission on every sale. At the very least, that calls their objectivity into question. Sometimes the products themselves are fine, but often they’re either outrageously priced or of dubious utility, or both.

For example, one top prepper site is pushing the Survival Still. I won’t link to it because it’s priced at literally fifteen times what it should be. Amazon has it for $284.95, which is pretty outrageous for what amounts to two modified stainless steel pot lids. (You supply the actual pots, one to hold the contaminated water, and a second one to hold cold water to condense the steam. You also supply the heat source and the fuel.)

What they don’t talk much about is that distilling water is extremely costly in terms of fuel, particularly with a device that is as thermally inefficient as this one. Much of the heat input will be wasted by radiation from the uninsulated source pot or by uncondensed steam escaping the device. And it requires a constant supply of cold water (ideally, ice) to work at all. Finally, the amount of output is likely to be pretty small. The manufacturer claims “approximately 1/2 gallon an hour”, but half that much is a more realistic estimate, assuming you have sufficient fuel to keep a pot of water boiling 24 hours a day every day indefinitely.

The company highlights comments by FEMA and the Red Cross that distillation is the most effective way to purify badly contaminated water, which is true, assuming that the water is contaminated chemically rather than just biologically. What they don’t mention is that it’s also the most inefficient and costly way to purify water that is contaminated only biologically, which is to say the vast majority of the water that most people would be using in an emergency.

In short, this is an effective water purification device, but one that is grossly overpriced, extremely expensive to use in terms of fuel, and overkill for purifying any but chemically-contaminated water.

Speaking of recommended items, Barbara and I fired up our Nesco Snackmaster Pro Food Dehydrator FD-75A yesterday to do some dehydration tests on seeds. Nesco dehydrators, which are Chinese-made, are the biggest sellers among dehydrators on Amazon, with US-made Excalibur dehydrators in a distant second place. Not surprising, considering that comparable Excalibur units sell for two or three times the price of Nesco units. I went with the less expensive Nesco unit because the reviews are similar and a dehydrator is, after all, a pretty simple machine–a heating element, a thermostat, a fan, and some trays.

We started by crushing one soldier bean seed with pliers, as a field-expedient dryness test. It fragmented nicely, telling us that it was already pretty dry and probably suitable as is for freezing. We then counted out three samples of soldier bean seeds. We weighed the first sample and stuck it in the dehydrator, set on low. We put the second sample in a 15 mL centrifuge tube, capped it, and stuck it in the freezer. After a couple of days to make sure it’s thoroughly frozen, we’ll do a germination test on those seeds. We started a germination test on the third sample, placing the seeds on a wet paper towel, rolling up the paper towel and sticking it in a sealed ziplock bag, and putting it on top of the refrigerator to sit for two or three days. Germination for that species is listed as 7 to 10 days, but that’s assuming the seeds are planted in actual soil. It takes them that long to poke up out of the soil. But all we need to verify is what percentage of the seeds germinate, which is obvious much sooner if we start them on a damp paper towel.

The next steps are to do a germination test on the dried seeds and to allow the sealed tube of frozen seeds to return to room temperature and then do a germination test on them. I expect both sets to germinate properly. We dried the first set of seeds for eight hour at about 86F (30C), which is cool enough not to damage the embryos. The mass loss was only 1.1%, which indicates that the seeds were already pretty dry when we started. The key numbers will be the percentages of germination for the three different samples. Once we have those, we’ll know how to proceed, at least for that particular species. We’ll then need to repeat the testing for each of the other species we intend to include in the seed kits, especially the critical ones, the other beans and the grains (corn, oats, and barley).