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Thread: Everything you ever wanted to know about dry food storage in Alaska Part 1

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    Default Everything you ever wanted to know about dry food storage in Alaska Part 1

    I just finished this for submittal to Alaska Magazine, thought I'd share it here too.
    Its too long for one post so I broke it into two parts.


    I’ve been doing a good bit of research over the last 3 months about storing dry food for my “just in case” cache. I needed to be absolutely sure since my family’s life will be at stake if we ever need it. I’m very glad I did too; otherwise I would have destroyed most of my cache if I’d simply followed what I’d found with a cursory Google search. Storing outside in a shed in Alaska (or other cold climates) is different.

    Alaska is particularly vulnerable to interruptions in food delivery from the lower 48, we’re remote and prone to earthquakes, tsunamis, volcanoes, and severe winter storms. Not to mention potential civil disruptions.

    Almost all of our food delivery goes through just a few fragile sea ports, mainly Anchorage. In an earthquake bad enough to damage the ports the airport runways will be probably damaged too so air freight is not really an option either, and in any case the sheer food tonnage required couldn’t be done.

    FEMA recommends a minimum of 72 hours of food, water, and medicine on hand per person. Other government sources (post-Katrina) recommend 30 days storage per person.

    This is also applicable for food storage in remote cabins or people who live way out in the bush.

    Food needs to be stored dry in an air & moisture tight container in a dark cool environment. The container also needs to be rodent proof.
    The most important factors are; storage temperature, oxygen, water content of the food & the air trapped with it, and finally light – in about that order.

    Containers: Regular plastic sacks or food grade HDPE 5/6 gallon buckets are only good for short term storage (<2-3 years) as oxygen will seep through the plastic.
    Your best bang for your buck is O2 blocking aluminized food grade mylar bags of at least 5 mil thickness, (7+ mils is recommended). These look like big thick versions of the silver anti-static bags that computer parts come in. Get the ones that need to be heat sealed (you can do it with a clothes iron) ziplock versions don’t seal perfectly.

    These bags are not rodent/puncture proof by any means so they’ll need to be protected by placing them inside another container. 5/6 gallon plastic buckets are ideal but rubbermaid type containers will do in a pinch.

    #10 (1 gallon) cans are best but they’re relatively expensive vs volume and you need specialized equipment to seal them.
    Large glass canning jars could be an alternative, but they’re fragile and they’re transparent (bad), you’d need to make sure the rubber seals would stay good for 10+ years. Personally, I wouldn’t use them.
    I guess metal paint cans could also work, but they’ll need to have a enamel lining and your food should be double protected from touching the metal by being inside a plastic bag. I don’t know how well these would seal either. I’ve never heard of anybody ever using metal paint cans.

    Temperature: For every ~11 F below 70 degrees the storage life is doubled:

    Temp F -- Years
    37.6 -- 40
    48.4 -- 30
    59.2 -- 20
    70.0 -- 10
    80.8 -- 5
    91.6 -- 2.5
    102.4--1.25
    So, in this example something with a 10 year standard shelf life stored at 59.2 degrees will last 20 years, something with a 2 year shelf life will last 4 years, etc. Conversely, if stored above 70 they will go bad that much quicker.

    Store your food as cool as possible but do not allow it to freeze unless you take strong measures to remove 97&#37; of the container moisture, more on that later.

    Oxygen: Air is about 21% oxygen and 78% nitrogen; the remaining 1% is other gasses. Food will oxidize all by itself in its container, eventually using up all the available oxygen – but by that time your food has gone bad (or rancid if it contains any oils/fats).

    In addition bulk wheat/flour, rice, beans, etc will almost invariably have insects eggs in it, if not the insects themselves - they’ll eventually die when all the available oxygen has bound to the food but by then they’ll have badly damaged your food, and who wants to eat dead bugs and old bug poop!

    Finally, make sure that you buy “washed” wheat/beans/rice/etc to cut down on the numbers of the little buggers to start with; it’ll also prevent dirt and other potential contaminants.

    So, at packing time you need to remove as much of the O2 as you can, quickly. There are two techniques used in conjunction that give the best results:

    - Purge the container with dry ice (or nitrogen) at packing time. Carbon dioxide is heavier than air and will displace the oxy/nitro atmosphere as it sublimates and fills up the container from the bottom. 4 ounces is enough to displace all the air inside a bucket but we’re looking to purge the air from inside the nooks and crannies of your food and this requires a bit of a flow so we’ll be putting in 6 ounces. Make sure you wear gloves when handling the dry ice; you can easily freeze your skin.


    - No matter what you do there’ll still be a little oxygen in the container and inside the food itself that’ll leach out over time so you’ll need to soak this up too. The easiest means to do that is to toss in a middling sized hand warmer inside the container when you seal it.

    You can spend more and buy “oxygen absorbers” online, but hand warmers are cheap, readily available, have the same ingredients (plus more salt as a catalyst), are non-toxic, and have a LOT of extra capacity that will remain and continue to scavenge micro O2 leaks over the years.

    Get the warmers that have their own water included. Don’t worry about them getting too hot, if you’ve done the dry ice treatment right there won’t be enough oxy in the container to let it get very hot. I you’re feeling paranoid you can wrap the warmer in a paper towel. *

    When the bag is sealed after the purging and O2 absorbing you’ll see that the bag will collapse itself hard to the food. This is happening for two reasons: First, you’re binding oxygen to the iron in the hand warmer and lowering the gas pressure inside your bag. Secondly, the food inside the container is actually absorbing the carbon dioxide and is also lowering pressure inside your bag; this does not change the food in any way. Both of these effects result in pulling a partial vacuum in your bag, it also serves as a visual confirmation that you got a good seal.

    Anything with fats or oils (including brown rice and nuts) is especially vulnerable to oxidation and hydrolysis , O2 & water removal is critical to long term storage. Look up “Rancidification” if you’re curious.

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    Default Part 2

    Water content. Dried bulk food such as beans/unground wheat/rice/pasta/etc has about 10% water and is fairly bulletproof and can safely store for 20+ years with a standard desiccant package inside the container to control relative humidity (RH) and storage in somewhat cool (but not freezing) conditions. Foods at 14% and above RH are in danger of allowing anaerobic (non oxygen using) salmonella to grow and produce the botulism toxin.
    Powdered whole milk, powdered whole eggs, peanut butter powder, flours, and bisquick, are “delicate” and do not normally last longer than 5-8 years in storage and need special attention for O2 removal and must be DRY to achieve a 20+ year useable storage life when stored at 60 degrees or less. For these we’ll need to get container humidity down below 5%.

    Desiccants; There are two types that you can find locally: Silica gel, which you can get at Wal-Mart or craft stores in their flower area, its used to dry flowers. The other is Calcium Sulphate, also known as dehydrated gypsum (aka drywall) which we’ll make ourselves. You can order either online, Drierite is the company that produces granulated calcium sulphate, both are food grade.

    You’ll need to understand relative humidity; it’s a function of water vapor saturation and temperature; as air cools down it can hold less water, the point when the cooling air starts condensing water is known as the “dew point” and its when we get dew or frost on everything. At a given temperature relative humidity is the percentage of water vapor in the air vs the maximum amount of vapor saturation before it starts condensing.

    Silica gel can pull container relative humidity levels down to about 30% RH @ 60 degrees, it works quickly and can and absorb 40% of its weight in water. It works best at 70-95 degrees but pretty much stops working at ~35 degrees. If it’s absorbed any water you’ll need to dry it out (regenerate) by placing a thin layer in an oven at 250 degrees for three hours, don’t go any higher than 300 or you’ll damage the beads. Silica gel comes in indicating (blue specks) and non-indicating (white), indicating is mildly toxic but it doesn’t matter because it doesn’t outgas and wont be touching your food anyway.

    Calcium sulphate only absorbs ~7% of its weight in water; however it works down to a dewpoint of minus 100 degrees and is completely non-toxic and is cheap. Its very effective at what we want it to do, we just need to use more.
    The other common types are clay, calcium oxide (quicklime), and molecular sieves. Clay doesn’t work as well as silica gel, quicklime is caustic & absorbs CO2, and moly sieves are expensive.

    Freezing conditions; THIS is why cold climates are different. If you are always going to keep your cache 40-60 degree conditions, silica gel will work just fine. HOWEVER if it’ll EVER be exposed to freezing conditions you’ll need to use dehydrated gypsum as silica gel will allow water to condense as it gets colder and allow portions of your food to rise above the critical 14% RH. Is it likely? Not really, but it’s not impossible for salmonella to grow at near freezing temperatures. In addition, food begins to break down by hydrolysis when RH levels get above 14% even in below freezing temps.

    Don’t try to use both as the gypsum can pull moisture out of the silica gel as the temperature gets lower which leads to elevated RH levels in your cache.

    To make your own dehydrated gypsum take white paper-faced drywall (NOT greenboard), take the paper off and break/cut it up into chunks no bigger than a pea, we want maximum surface area here, drywall is actually foamed so it already has lots of surface area. Spread it out in a pan (1” layer) and heat it up in the oven to 435 degrees for 3 hours.

    Make SURE you don’t go above 480 degrees or you’ll convert the gypsum to a anhydrous form that isn’t water soluble even in geologic timescales unless it’s a atomically fine powder. Put a reliable oven thermometer in the oven to make sure, oven temp dials can be very unreliable.

    We’re converting the gypsum to a form called γ-anhydrite and driving off other stuff the drywall has in it and absorbed from the environment. Drywall has plasticizers, foaming agents, EDTA, and starch in it from when it’s made. It’s all non-toxic and does not outgas except for the naphthalene or esters plasticizers, temperatures above 425 degrees drive these off.

    After we’re done, pack our desiccant packages into bags of about half again the size of a tennis ball, you can use double layers of coffee filters or strong white paper towels (I used Viva), close the openings using white zip ties, we don’t want to use the black ones which may contain a dye we don’t want in contact with our food. Put your desiccant bags into a airtight container until use. One of these bags should be good for a 5 gallon bucket. *

    Personally in my eggs, bisquick, and milk I put two in just to make sure. Don’t use a rigid container like a pill bottle as it may break when the mylar bag crushes down from the vacuum the O2 removal & CO2 will cause.

    Putting it all together: Now, finally, lets package our food. Line your buckets with your mylar bag, brush off any water frost from the dry ice surface and put 6 ounces in the bottom of your bucket (that’s lined w/ a mylar bag) and pour fill the bucket about half way.

    Put one or two of your desiccant bags and then pour the rest of your food in. Make sure you’ve left yourself enough bag to close the mouth flat.

    Close and fold over the mouth of your mylar bag shut with clothes pins or document clips, we don’t want a airtight seal just yet. I found out the hard way that “chip clips” aren’t strong enough.

    Don’t shake or disturb the bucket while purging. After dry ice is sublimating open up one or two of your hand warmers and toss them in, try not to disturb the inside of the bag - we don’t want to mix our CO2 gas and ambient air, then clip the bag shut again. You’ll know its done sublimating when the bottom of the bucket is no longer cold, it’ll take about 2-4 hours.

    Now clip the bag mouth flat on a 1”x2” wooden board, “burp” the bag of the remaining gas then take a clothes iron on “wool” setting and smoothly iron the bag mouth shut. You can also use foodsaver type sealers to do this. Make SURE you don’t have any wrinkles, the wider the ironed seal the better.

    Leave the bucket/bag in a relatively warm area (50-70 degrees) for a few days to give the desiccant a chance to remove most of the moisture, leave the bucket lid off so you can verify you got a good seal on your mylar bag.

    After a few days go ahead and store it wherever you want. I’d recommend you leave it in a above freezing area for a week or two before exposing it to freezing temps. Don’t worry about the water in the hand warmer, the desiccant will pull the water out of it fairly quickly (which is why the hand warmer needs to work fast).

    By the way, beans stored for a very long time or in very low RH levels can become “hard seeds” which resist re-hydration by soaking in water. Scratch the seed/bean outer coat a little before soaking, or put the seeds/beans in a warm higher humidity environment for 3-4 days before cooking and they’ll rehydrate just fine. In addition, rice might have split in storage in low RH conditions, it rehydrates and cooks fine with a couscous texture.


    * Legal disclaimer; neither treated drywall or hand warmers are certified for use in contact with food items. To comply with FDA regulations buy authorized "food grade" oxygen absorbers and dessicants.


    By David A. Harrison

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    Default Edit 1

    Salt, white sugar, honey, and Karo corn syrup have indefinite shelf lives right in the bag/bottle, the salt and sugar might turn into a solid brick requiring you to chip off and grind it up but it won’t go bad. Honey and Karo syrup may crystallize in the bottle over time and/or if exposed to freezing temperatures, immersion in hot water will dissolve these crystals.

    This article is primarily about how to store dry food, what to store is another multi-page article altogether!

    Copyright reserved by me David Harrison, released here for personal use only.

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    thanks for the info ..

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    Great Post, Thank you......

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    Thumbs down Bad information

    David,
    I have to disagree about the post. I saw the disclamer about the gyp board and the hand warmers but all that is saying is don't do it the way I said to do it. So I think disclaimers are really important to read.

    Advising people (then not in a foot note) to use non-food grade items to store food is not a good idea. Be forewarned that the gypboard that comes from China has toxic chemicals that leech out and make you sick, corrode metal, etc. Do you really want that in your emergeny food storage? There were a bunch of homes that had it installed in the south that was causing people to get very ill.

    Then to use hand warmers in the food....makes me leary of what is in the warmer. Yes the products in most of the warmers may be edible but the intent of the warmer is not to use it as food or in the preperation of food. Therefore it does not have to be inspected as a food product or as a product used for food.

    One might argue that the silca gel is not edible, this is true. But it is manufacturered with the intent to be used with food. So it has to be inspected as such. After all it is a form of sand.

    I would advise not to use non-food grade anything for food storage. I'd rather pay a little more and sleep at night knowing that the items keeping my food safe was indeed safe itself.

    I am not trying to bust your balls here, just trying to keep bad information out of the food storage.

    http://news.yahoo.com/s/ap/20091023/...product_safety



    http://www.examiner.com/x-4592-Birmi...ng-people-sick

    http://www.hadd.com/node/1581

    http://www.nytimes.com/2009/10/08/bu...aozRzbAqOHN/2A

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    most of my long term food was packed and stored in 5 gallon sized buckets with bags and sealed as need by walton feed company

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    Mine are sealed in mylar bags using the dry ice method and two silcia packets. I did it myself. Walton feed is one of the best places to get the food from.

    Side note...Henry are you up in AK now?

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    I saw this story came out today about the chinse drywall.

    http://online.wsj.com/article/SB1256...googlenews_wsj

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    I went with food grade mylar bags inside 5-gal buckets from Lowes. Food grade O2 absorbers in the bags to get rid of the oxygen.

    One thing to note, make sure you can cook and eat the stuff you store. Also have variety. 2 months of eating nothing but bread the density of a brick because all you stored was 200lbs of wheat without any idea on how to make bread, might make you wish you had starved to death.

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    Hi James, thanks for the feedback! You raise some good concerns.

    I was aware of the chinese drywall problem, and looked into it when I was researching the ingredients in drywall:

    The US is no longer importing drywall from China because of the problem, in addition the affected drywall was primarily shipped to Florida and surrounding states from 2003 to 2007 but isolated instances have been found in other states including Washington state but NOT to Alaska.

    In addition I found that when the affected drywall is heated it gives off a STRONG rotten eggs smell which would be a indicator to not use it. I didnt put it in the article with the thought that people in Alaska wouldnt be exposed to the problem and to save a bit on a already long article. I didnt give any thought to people other than Alaskans reading it and I should have.

    Since you brought it up I'm sure others will be concerned too so I'll go ahead and amend the article with the info I found and to direct people to use drywall only manufactured in the United States, which has surprisingly strict manufacturing standards for drywall.

    Also

    When researching the ingredients in hand warmers I found out that they actually are manufactuered to food grade standards.

    The reason being that the intent of hand warmers is to be pressed against skin, usually a sweaty moist environment and if there are any toxins in them they could affect the person using them. This applies to the ones imported as well as the warmers manufactured in the US.

    I even found a few medical reports of people (usually kids) eating them with no ill affects (other than panicked parents), a couple of those reports were from China. Dogs also seem to think they smell good enough to eat. (shrug), on the other hand dogs also eat cat poo all time. The reports from that arena also show no ill affects.

    The ingredients in warmers are iron, water, cellulose, vermiculite, activated carbon and salt.

    I'll include all this in the article too.

    The whole point of my research was to make sure my family and I would be safe using our food cache, I had to be absolutely sure it would be okay. Because I'm a geek I ended up digging into gnats @ss details about everything involved.

    The publication article grew from me talking to my friends and coworkers about what I was finding out and learning and they said "thats a lot of really good info, you should write up a article and see if you can publish it" I had no idea it was going to end up being such a big project.

    I also should put in a blurb about rotation of food.

    Unfortunately the submittal guidelines for Alaska Magazine say 2200 words, I'm at 2950 already.

    Linkage

    http://www.doh.state.fl.us/ENVIRONME...r/drywall.html

    http://www.warmers.com/Pdf/NonToxic.pdf

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    Hi Rick You're right, we need to store a lot more than just beans and wheat, definately need a variety. There's even a term for it: "diet exhaustion"
    I got a bunch of veggies and fruit from honeyville grain (great shipping)

    I didnt get into what to store because thats a whole multi-page article in and of itself! There are lots of good nutrition guides online for emergency food storage.

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    Maast,
    Sounds like you are on top of it. Thanks for taking my comments in a positive manner. I meant them in a good way. I think the use of sheet rock and hand warmers are a novel and clever way to use them. But I would not personally use them in my food storage. But if you can get people to prepare than I think you have done a service to all.

    Just a thought maybe you could try and get them to do a two or three part series on food storage. As you stated there is alot more than what you covered...but you are bound by the allowed length of the article.

    Keep us informed when the article gets accepted and printed.
    Thanks again for the postive attitude.
    James
    Last edited by JamesM; 10-29-2009 at 13:47. Reason: Spelling

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    Default I'm a barking idiot

    I was just out in the garage hammering away and more drywall to get the paper off (which BTW is a huge pain in the butt) when I realized there are MUCH easier and cheaper sources of powdered and pellitized gypsum than drywall, and it doesnt have anything else in it but gypsum.

    I was hammering away and happened to look over at the gardening stuff.

    There it was, the remainder of a 40 pound bag of gardening pellitized gypsum that I think I bought for about 15 bucks a couple years ago.

    Its pure gypsum, nothing has been added to it, its already pellitized, I dont have to hammer it into dust and chunks and get cr@p everywhere.

    I'm an idiot. I got so focused in drywall I never even considered other sources of gypsum.

    I've got to rewrite the article.

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    iam up in anchorage for right now ..intill i get the place going next to the family homestead ..

    i been looking at the walton feed and a shipping a patch of supplies to the cabin ..for i allready have a set of bulk supplies i need ..i just need to add a few more items to for a long term iitems i need ..

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    Hey Maast seems like there are more stories poping up on the drywall. This one is on MSN today.

    http://articles.moneycentral.msn.com...aspx?gt1=33004

    I would think if you can leave out the mention of drywall all together it would be a plus. Great find on the gardening gyp!

    FYI for the food grade buckets just go to a bakery, or a supermarket bakery, or donut shop and ask them for their buckets. They just throw them out. Plus they have 2 1/2 gallon 5 gallon and 6 gallon sizes....for free.

    I use the Gamma tops that have the seal in them. If you think about it 5 gallons of anything is a lot of food to be opening and closing the lid for when you go to use it. It makes it easier, after all who needs the added stress if you are actually having to use your stash? (Which you should and keep rotating your stock.)
    http://www.usplastic.com/catalog/pro...uct%5Fid=20669

    It is amazing how much info is out there. Maast I think you have quite a challenge to keep your article short...lol. Keep ys informed of the progress!

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