Testing Greasy Wool
[Sorry ... Here's another page that needs a bunch more work ... but I'm working on it, periodically ... I've taken a few shots at it already. Also, I'm definitely not claiming any expertise here, but this is the best info I've been able to come up with. It's my best understanding of what Padula has told me, plus some other reading I've done. But any inaccuracies are purely my own fault.]
Greasy Wool -- that is, the wool as it is shorn from the sheep -- must be tested so that wool buyers know its properties.
There are only a relative handful of facilities/people in the USA that have the equipment to properly sample the baled greasy so that the test lab is working with fiber that truly represents the content of the bale. One such facility, Roswell Wool, is where our wool is usually sampled, although the Innes Clip of Batch 9 was sampled at Bollman, in Texas, in 2022. In 2023, the Innes Clip was sampled at the Innes Ranch by a longtime wool-industry broker -- THANK YOU! Advisor Bob Padula helped develop the sampling techniques.
In the USA, for 56 years, greasy wool testing was done by Yocom-McColl Labs, but proprietor Angus retired in 2019 at age 86 or so. As of 2023, our wool is tested partly at Texas AgriLife Wool & Mohair Sims Lab at Texas A&M University in San Angelo, Texas and partly by New Zealand Wool Testing Authority. [Given WeatherWool's very strict 100% American material and labor policy, I'm not happy about this situation, even though NZ is AOK in my book. However, this is a testing service, not raw material or processing that goes into our products. And since Angus retired, our friends in NZ have been doing the testing for us. THANK YOU NZ!
The Sims Lab at UT tests for fiber diameter and percent of vegetable matter (VM -- grass, seeds, etc.). The fiber diameter is absolutely critical to us, and we require low levels of VM. Most people in the USA don't require "length and strength" testing. But the length and strength of the fiber is also very important to us. So although Sims began testing in 2023, we still had to send to NZ for length and strength. Long-term, we have also heard that Sims A&M does not plan to obtain the equipment needed to run all the tests we need. We'll see ...
In spring of 2023, Mike Corn of Roswell Wool told me (that's why he's an Advisor!) there are other full-service testing facilities besides NZ. And an easy-as-pie search turned up the list of Testing Labs licensed by the International Wool Textile Organization. There are also labs in Argentina, Australia, South Africa, Uruguay and Wales. The Wool Lab at the University of Montana, which I visited in August of 2022 (Blog entry of 3 August 2022), does testing on an informational, rather than commercial basis. I'm interested in getting additional tests done by another lab or two so we can double-check.
The lab reports provide a lot of information. Most important to us:
- Fiber Thickness
- Variability of diameter
- Expected yield after scouring (cleaning). Price of a clip is based in part on the expected yield of clean fiber
- Amount of vegetable matter (grass, twigs ...) in the fleece
- Length of the fibers
- Strength of the fibers
- Where on the fiber breakage occurs when stressed
- Presence of paint. Some ranchers paint numbers on their sheep, but we avoid painted fiber
- Presence of polypropylene in the fiber ... we avoid it
- Age of the sheep. The lamb's wool (first shearing) is normally, but not always, the finest (smallest diameter) fiber that sheep will grow in its lifetime
I may eventually add here more specific info regarding the criteria by which we select fiber, but as present I'm deferring, at least for a while, to those (please see Blog of 2022-07-23) who advise me to keep some cards close to the vest.
Roswell Wool is America's largest warehouse and auction house for fine wool, and Advisor Mike Corn is one of the partners at Roswell. With the assistance of Mike and (mostly) Bob, we evaluate the lab reports, determine which lots of wool are best for our purposes, and bid on them at Roswell's auction.
"Traditional" American testing has focused on fiber diameter, expected yield after scouring, and amount of vegetable matter in the greasy. Americans have paid much less attention to fiber length and strength. For us, the traditional US testing was vital, but not sufficient. Maybe someone else has tried to produce Hardcore Luxury woolen fabric, but not as far as we can tell. And so, our need for length and strength testing is unusual for US wool buyers. But it was pretty cool that testing of the Innes Ranch Clip confirmed the length and strength I'd been told to expect, even though the Innes fiber had not been tested for length and strength. Standard American shearing and wool-classing practice requires the shearers estimate length and strength of any clip expected to measure over 50 mm (about 2 inches). Any fiber that would be of interest to us is a lot longer than 50 millimeters.
And the rub is that testing for length and strength requires different sampling techniques and different lab analysis equipment than does testing for fiber diameter, yield and vegetable matter.
Wool is sold to industrial buyers in bales that weigh about 500 pounds (225 kg). And most industrial lots will contain multiple bales. WeatherWool is tiny compared to some buyers. And the ranchers from whom we buy are also sometimes small. We routinely buy lots with 10 and 20 bales ... sometimes even only two or three bales. Getting truly representative samples is critical, and difficult!
Adding to the difficulty is the fact that length/strength testing differs from diameter/yield testing in both required analytical equipment and sampling techniques and sampling equipment.
Length and strength testing requires "grabbing" samples whereas fiber diameter and yield testing requires "core" samples.
When testing for length and strength it's critical to maintain the integrity of individual fibers. And so the grab tests must be done first. Grabbing is pretty much what is sounds like ... grabbing samples of fiber from many different places within a given lot of wool.
Coring involves insertion of an instrument into the bales (in many places) to obtain tiny samples because the test results are not influenced by whether any fibers are cut.
The NZWTA will perform whatever testing is ordered. Many American buyers don't ask for length and strength and so those tests are not automatic, even though they are much more usual for the testing of wool from Australia and New Zealand. In years past, some people who wished to buy American wool could not comfortably do so because critical tests were not performed.
We learned some of the preceding material during July/August of 2022, when Debby and I were on the road.
- We spent about 24 hours at Padula's PM Ranch (THANKS SAMANTHA and BOB!!) and learned a lot. Bob's sheep needed vaccination, deworming treatment and weighing, and we helped a little. And Bob gave me some books to study, one of which is Code or Practice for Preparation of Wool Clips, from the American Wool Council, a Division of the American Sheep Industry Association.
- The day after we left Padula's, we reached the Innes Ranch in Gillette, Wyoming. Wyoming produces a large quantity of wool with characteristics that interest us, but painting the sheep is common in Wyoming, and we avoid painted wool because paint can cause problems downstream. Innes has never used paint.
One thing I learned at Padula's is that wool must be tested at standardized temperature and humidity. I can't supply the details of the standards, except I remember Bob saying the wool must be stored at least 8 hours in the standard environment before testing.
14 May 2023 --- Ralph