Pipe tobacco must be moist enough to be "workable". It doesn't necessarily need to be sopping. But in order to get the "edge to edge" tightness or tautness during the pack, it must be pliable, nevertheless.
Rehydrating pipe tobacco in the same manner as cigars is tedious. And unnecessary. Cigars are rehydrated slowly because a fast hydration (or dehydration) will very likely damage the wrapper and render the cigar useless. The cigar, throughout its structure, must take up moisture uniformly. But with pipe tobacco, this is not an issue.
I have found that, with bone dry tobacco, the amount of water needed to rehydrate properly is about 1.5 teaspoons for every approximate 2 ounces of tobacco (slightly adjust as desired). No need to weigh the tobacco. Use a 2 oz can, 4 oz can, etc. to approximate the volume needed.
There are a few ways to approach this. One can simply place the desired volume of dry tobacco into a lidded container which is at least twice that volume. Add the distilled/filtered water, put on the lid, and shake the container to distribute the tobacco and water evenly. Leave on the container and slightly rap the container to knock excess tobak stuck to the walls. Let rest for a number of hours until the moisture equalizes.
There are variations on the method. If one doesn't have a suitably large container for mixing, one can add the target amount of water to half of the target of dry tobacco. Follow the procedure as above, and then mix in the moist tobacco (very moist) into full amount of dry tobacco.
This technique can also be used with "ready rubbed" flakes (e.g. Mac Baren Virginia #1).
RECIPE (This is a working maximum. If necessary, adjust water ratio downward to personal taste)
- 1.5 Teaspoons Water per 2 Ounces Tobacco
- 1 Tablespoon Water per 4 Ounces Tobacco
- 2 Tablespoons (1 fluid ounce) Water per 8 Ounces Tobacco
- 4 Tablespoons (2 fluid ounces) Water per 16 Ounces (1 Pound) of Tobacco
- Though I've not tried this method with full flakes (because I don't have any bone-dry flakes lying around), I'm considering this extrapolated method:
- Lay down a sheet of Plastic Wrap.
- Lay down a dry flake on the Wrap.
- Quickly dip a dry flake into a cup of purified water and allow to briefly drip.
- Place the wet flake on top of the dry one.
- Place a dry flake on top of the wet flake.
- Repeat with alternating wet and dry flakes until done.
- Wrap up the pile in the Plastic Wrap
- Allow the moisture to equalize.
- Thoroughly remix the leaf, so as to distribute possible moist "pockets".
- If, after moisture equalization, the tobacco is too wet for one's preference, simply mix in some more bone-dry leaf.
- A variation may be able to be used with plugs. Quickly dip the entire plug into water and wrap in plastic wrap until the moisture has equalized. Repeat the process as necessary until the desired moisture content is reached.
DISCLAIMER: If the possibility of mold is a concern, one should simply hydrate as much as one plans upon using within a reasonable amount of time. YMMV.