Purchasing reed cane, whether it be gouged only, gouged and shaped, or gouged shaped and profiled, can be very nerve racking because we don't know whether the reed cane will turn out to be a decent reed.
In dealing with the experience of bassoon reed making, I have established a few ways that might help you determine a good piece of reed cane and to give you a basis for continuing the reed making process.
First of all, when your cane arrives, take a good look at the underside portion of the reed cane. Follow the fibers or parallel lines from left to right, making sure these fibers are straight and parallel with each other and not curved or arced. If these fibers tend to be arced, chances are the vibration and balance of the reed will be incorrect. Now look at the sides of your reed cane, I do this to determine whether the gouge is even on both ends. In many cases, you will find that the gouge is slightly uneven. As a result the finished reed may have a balancing problem, and this will cost you precious time to correct.
I purchase my reed cane in its gouged form. From profiling many of these pieces, I have noticed that some pieces of cane will profile much easier than other. (All of this cane was soaked in cold water for approximately 3 1/2 hours before profiling). I then separated the easier pieces from the harder pieces. It turned out that the easier pieces of cane didn't seem to satisfy my needs, and the harder pieces of cane were more promising. Keep in mind, that in order to develop this feel of hard and easy, you must profile several pieces of reed cane. Let us now assume that all of the cane has been removed from profiling. Rub your finger tip up and down the profiled surface and make sure your finger tips are oil free. (We want to try to keep the profiled surface as clean as possible). By doing so, I have noticed that the softer pieces of cane appeared to have a roughness to them and the harder pieces appeared to have a smoother plane.
At this time let us form the reed cane into the reed blank. Forming the reed cane with the proper mandrel or mandrels, whether it be soaked or dry, I noticed that the good pieces of reed cane profiled were much harder to form than the softer pieces. That is, the twisting and pushing process that I needed for forming required more energy for the harder profiled pieces. Once again I separated those reed blanks that were easy to form from the harder ones. By carefully looking at these blanks, there was a tremendous difference in the shape around the throat area and especially around the area of the second wire. The softer pieces of reed cane that were easy to form had a much rounder, crushed look than did the harder pieces. Again these touch-feel processes will be developed with practice.
Now that the reed blank is formed, let us cut the tip. At this stage, I attempt to crow on the reed blank even though the cane is rather thick, I place my lips up to the first wire and begin to blow air into the reed very gently. Keep your embouchure loose enough in order to feel and hear the first crow sounds. If the crow pitch is high (F-F# -G), this will indicate to me that the reed at this stage is promising. If the crow pitch is lower (E-Eb-D), and has too much freeness, this indicates that by the time all the cane is taken off (to call it a finished reed.) the reed will be too soft and the crow at this time will have a squawky, low sounding quality. If I do decide to keep a reed like this, I would have to resort to other measures for correction (cutting the tip again or adjusting wires.) By this time after considering all these observations. I could pretty much determine a good piece of reed cane from a not so good one.
This method of testing reed cane is only one of many. This method has worked for me and I think it will work for others as well. If you take the time to look over your cane and be a bit more picky with what you are working with, this might save you time, and hopefully bring forth a better reed.