1) Get a clean food-grade bucket and lid. If it's used, make sure it was used for food. Food grade plastics are denominated by a number inside three chasing arrows (the recycle logo). Numbers 1 and 2 are best. 4 and 5 are OK if you use a Mylar liner. 3, 6 and 7 are not OK. Edited to add from the tips posted below: You can use anything, a carboard box, a tupperware container or nothing at all if you are using a mylar bag. The bucket only gives mechanical support to protect the bag and make them stackable and provides a container to eat from later. A good bucket is more important if you don't use a liner. But you should use a liner.
2) If you are using a Mylar liner, squeeze all the air out of it, then inflate it in your bucket with CO2 or Nitrogen. CO2 and Nitrogen are heavier than air so an open top won't release all the gas. The more air movement you have the more air will get into the bag though. Alternatively if you aren't purging the air, just put the liner in the bucket and open up. No big deal. In the picture you can see that there is a lot of extra bag sticking out of the top, there will be less when the bag is filled but still plenty to open and reseal the bag a few times.
3) If you are purging the air, put in a desiccant pack sized for your bucket. If you are not purging the air, put in an oxygen absorber sized for your bucket. If you are using undersized dessecant or oxygen packs and have to use more than one, put some in the bottom, some in the middle and some on top. you can use an oxygen absorber if you have purged the air as well, doing double duty on oxygen removal. (what I generally do) The picture is of a 20 pack of oxygen absorbers. The pink eye tag is an exposure indicator, it turns blue when exposed to oxygen or open air so you know the absorbers are good if it's still pink.
4) Put what you are putting in the bag in the bucket. Just pour it in. Yes this will disturb your purging gases. Fill to about 1" of the top of your bucket. In this case, white wheat.
Toss those oxygen absorbers right in with the dry food. They won't harm the food, just don't eat the little packets and you are fine. I'm using two absorbers in this picture and one I'll push down into the food, the other I'll leave on top of the food. If you get them sized right when you buy them you only need one.
5) If purging, put your gas hose into the bottom of the bucket and purge again. Do some math and make sure you use enough gas, and gently put it in, don't blast it in. Here's your math: One Gallon is 0.133680556 Cubic Feet. Therefore a six Gallon bucket will be 0.802083333 Cubic Feet. Set your regulator for a delivery of less than one Cubic Foot per Minute (CFPM) and wait a minute, literally. Like time it. No harm in putting in more, just make sure you put in at least this amount of gas.
6) If using a Mylar liner, now is the time to seal it. Pull the bag top taunt and seal away.
Make sure you squeeze the air or gas out of the top of it so it will all stow in the bucket. The way I accomplish this is seal 90% of the seal but leave an inch or two unsealed at one of the sides of the bag. Then fold/squish the bag into the bucket, pull out that unsealed corner and seal it. If you just seal it up without smooshing it down, it'll never fit in the bucket.
Make sure you check your seal to ensure it's a good one. If you have a lot of extra room at the top of the bag, seal it as near the top as possible. This makes the bag reusable later.
7) With scissors, make a little snip that'll let you open the bag later without a knife. Don't go too far and ruin your nice seal. I dare you to get one of these bags open with your bare hands.
8 ) Put your lid on but don't snap it down just yet.
9) Label it. Right now. Date it. Put the contents on it. Don't put it on the lid either, or if you do make sure you put it on the side too. It's hard to read lids when they are all stacked up.
10) Wait three days for the oxygen absorbers to do their work. It will look like the food is getting vacuum packed. You want to wait on snapping the lid down so you can check and make sure this is happening for two reasons, A) you want the oxygen absorbers to be working and B) you want your bag seal to be good. You have to wait to make sure this is happening. then
11) Snap on your lid. A big rubber mallet will come in handy, otherwise I find standing on the bucket works fine too. Using the palm of your hand will hurt after a while.
Oh, and this is not just for grains. You can store ammo, metal parts, candles, whatever you want this way. Moisture and air are your biggest enemies in long term storage (food and other stuff) and this is a pretty good way to store stuff.
Some myths:
- Basil, Bay Leaves and such do nothing to discourage bugs in your sealed up grains. Don't waste them by putting them in your food.
- Purging air is useful and easy, oxygen absorbers are even better.
- Oxygen absorbers absorb atmospheric oxygen. Dessecants absorb moisture. Know the difference. Neither is bad to have contact dry foods. Neither is poisonous, just not good for you. You can use them together.
- You CAN use a household iron to seal your Mylar bags. Preferably one with a teflon sole. Check your seals though. A sealer is a great investment but don't let the fact you don't have one stop you from putting away some food.
- You can use a bucket without a bag. A bag costs $0.82. It's cheap insurance. Get them. I have made good bread from grain that was 20 years in a bucket that was air purged with dry ice. It was fine. But $0.82? Get one. It's better to use a bag with no bucket than a bucket without a bag. Using both is better though.
- Temperature matters. Store your food in a stable lower temperature location. With the bucket and liner moisture isn't so important, constant temperature is important.
SUPPLIES and SUPPLIERS
- I use and like www.SorbentSystems.com for mylar bags, sealers, oxygen absorbers and dissacant.
- Doc66 recomends www.usaemergencysupply.com.
- www.airgas.com is a national gas and welding supply company. They have bottled gases, regulators and dry ice.
- A 20"x30" or better sized bag will line a 5 or six gallon bucket.
Edited: Added some pictures, more to come later.
Our furnace has no water pump on it, and we were tired of tripping over the hard line we had running across the laundry room to the drain. So, we put a bus bin under the drip, thinking there was no chance we'd go a whole day without one of us going into the laundry room. Of course, that day happened, the bin overflowed, and crept along the floor. The water seeped under the paint in areas that looked like had already been weakened by previous overflows from the last owner (we've only been here 1.5 years). 
