In a thread sometime ago I asked for input about the sometimes confusing jargon used to describe shaving brush attributes (in fact I subsequently took my user name from the discussion). Lately I've seen a number of posts querying this brush language. I thought it might be helpful to revisit the topic in a new thread. I'll lay it out as I see it and if anyone wants to add their input please feel welcome. This is my take. Others may (emphatically) beg to differ. Hope it helps.
Scritch: As per the Wiki glossary — a hybrid word of scratchy & itchy. I would toss “prickly” into the mix too (although I expect “scratchy” was in fact meant to include prickly). Is scritch a positive or negative characteristic though? I guess it depends on who’s perceiving the scritch and how much scritch there is. Personally, I don’t love it. Most examples of Simpson’s Best hair have some scritch. A few — the B&B LE/Simpson Eagle G3 in Best comes to mind — are virtually scritchless, similar to Simpson’s Super grade. Shavemac’s Finest has some scritch — although I think less than Simpson’s Best. Thater has no scritch. The original Rooney Heritage hair had no scritch.
Scrub: Distinct from scritch, scrub is a sense of friction from the brush hair as it is worked on the skin but is not connected to scritch. In other words a brush may be scrubby with or without feeling scratchy, itchy or prickly in any way (e.g. above-mentioned Eagle G3 in Best or Chubby in 3-band super). Conversely a brush may be scritchy without being scrubby — a Shavemac 22709 Finest comes to mind. Some knots, like the Thater 3-band, have neither scritch nor scrub. With a Thater, IMO, the feeling of the hairs working across the face is virtually imperceptible; the feel is indistinct from simply being able to feel that the knot is making contact with your face. Some people describe scrub as the brush exfoliating the skin.
Softness: Two kinds — soft tips and soft knot. The softness of the hair tips is inversely proportional to the amount of scritch present in the tips. Very scritchy and very soft tips don’t coexist. However, scrubby and soft tips may very well coexist. Softness of the overall knot describes how much flex there is in the knot when pressure is applied. An extremely soft knot may need very little pressure to flex or even collapse; this kind of knot may be referred to as floppy. Knot softness and scritchiness (of the hair tips) may coexist.
Density: Density refers to the volume of hair present in the knot. The more hair there is, the denser the knot. Denser knots tend to be more expensive than less dense knots. If two brushes by the same manufacturer have the same grade of hair, knot dimensions and insignificantly different quality handles; and one is much more expensive than the other, often the cheaper brush is less densely filled with badger hair. A densely filled brush may — but not always — have more backbone than a less densely filled brush. A notable example of less densely filled brushes with superior backbone are many 2-bands (the distinct qualities of 2-band versus 3-band knots is beyond the scope of this post but there are numerous other threads on the subject).
Backbone: Backbone refers to the stiffness or lack of flex of the knot under pressure. The amount of backbone a brush has is inversely proportional to how floppy a brush is. As mentioned above, backbone tends to increase with greater density — but not always. Greater backbone equates with greater scrubbiness.
Flow-through: Flow-through refers to how easily the lather within a brush is released onto the face. It is distinct from a brush’s ability to whip up a good lather in the first place. When a brush is described as being a lather-hog, it means it has below average flow-through. Flow-through is affected by the interplay of several of a brush’s attributes; the grade of hair, density of the fill, diameter and loft of the knot contribute to a brush’s flow-through. Shavemac and Thater 2-bands, Savile Rows, and many Simpsons are known for their superior flow-through. But flow-through is not always superior in some of the most revered brushes such as the Simpson Chubbys or denser Rooneys. Those brushes are valued for other superior qualities. Some will argue that all brushes can have great flow-through as long as they are loaded with enough soap or cream. I don’t subscribe to this theory personally but there may be some truth to it.
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