This is a simple experiment to help one understand the concept of Radial Density/Core Ember, how to achieve it, and how to recognize when one has achieved it.
What You'll Need
- Three pipes with various chamber gauges: one narrow (17-19 mm), one medium (20-22 mm), and one wide (23-25 mm). Try to start with the narrowest that one has, preferably 17-18mm, but the more-common 19mm will do in a pinch. Regardless of one's particular selections, try to make the difference between each size at least 2mm.
Note that the most common sizes on the American market are 19, 20, and 21 mm (3/4", 13/16", and 14/16" respectively). This is not really enough of a spread for a good experiment.
- A rather loose, fluffy-cut tobacco that's not too dry. Something in a cavendish-cut would work. Make sure that the blend is not too stringy. Tear clumps of leaf in half and in half again and again to shorten the strands, if necessary.
- Load the tobacco into the widest pipe using the CIRCUMFERENTIAL PACKING described in the Wos Method. Never press straight down on the tobacco pack.
CIRCUMFERENTIAL COMPRESSION/PACKING - A method of packing which, rather than pressing the leaf straight down into the chamber, uses gentle pressing together of the tobacco from the around the rim of the chamber toward the central hub. Picture the process in the following way: Imagine mounding a large volume of shredded newspaper over the open top of a coffee can. By using both hands and circumferentially compressing the mound of shreds towards the center of the mound, the mound of shreds will slowly slip down into the can.
- Clean off the rim to level the tobacco.
- Now, examine the "feel" of the top of the pack: its density and texture and "surface tension". Notice that there seems to be a sort of round "core" of tobacco in the center of the chamber; a circle within the circle of the chamber, if you will.
- Repeat the above in the medium gauge chamber. Is there still the same core, the same sort of feel? There may or may not be. If there is, one may well have hit upon the "minimum permissible gauge" for that particular cut.
- Repeat the process again, now in the narrow gauge chamber. Almost invariably, one will find that one is unable to achieve a "core". The surface will be soft and loose, a jumble of unmeshed strands with no structural "surface tension". No "circle within a circle".
Note: Theoretically, one could always try breaking down a blend's cut a bit more in order to accommodate a narrower bowl. However, having a variety of bowl gauges is makes one's options easier.
For more detailed info, the complete Wos Method can be found HERE.