Most beard washes are liquid surfactants in branded bottles, sold at a markup and heavily fragranced. A good cold-process bar does the same work, often better, and rarely leaves anything behind.
A beard is two things at once: the hair you see and the skin underneath it. Both need cleaning, and the second is the one most people forget. Sweat, sebum, and the residue of whatever sits on the surface all collect at the root, against the skin. A wash that conditions the hair while ignoring the skin solves half the problem.
What a beard actually asks of a cleanser
Beard hair is coarse and absorbent. It holds scent, holds oil, and holds product. The skin beneath it behaves like any other facial skin, it can be cleaned, dried out, or left comfortable, depending on what touches it and how often.
A cleanser for a beard needs to do two unremarkable things well: lift oil and residue from the hair, and reach the skin without stripping it. A balanced bar soap does both. The cleansing power is sufficient for coarse hair, and a well-cured bar tends to leave less buildup than a thick liquid wash, which can coat the hair and dull it over repeated use.
The method, plainly
Wet the beard thoroughly with warm water. Cold water won’t soften the hair enough; very hot water draws moisture out of the skin underneath.
Work the bar into a lather in your hands rather than dragging it across the beard. Dragging a bar through coarse hair is inefficient and tugs at the skin. Once you have a proper lather in your palms, massage it through the beard, working down to the skin with your fingertips. The skin is the point. Lather sitting on the surface of the hair has done nothing for the root.
Rinse completely. Beard hair holds soap longer than scalp hair does, and residue left in is what makes a beard feel stiff or itchy as it dries. Rinse until the water runs clear and the hair feels clean rather than coated.
How often, and why not more
Two to three times a week suits most beards. Daily washing tends to over-dry both the hair and the skin beneath, and the skin under a beard is already prone to feeling tight when its natural oils are removed too frequently. On the days between, a rinse with warm water is usually enough.
If the skin under the beard feels dry, the answer is rarely to wash more, it is to wash less aggressively, and to condition afterward. The principle is close to what applies elsewhere on skin that has been through something: once a barrier is intact and clean, gentleness does more than frequency. The same logic that governs washing skin while it is still settling holds here, clean thoroughly, then leave it alone.
What to keep away from a beard
Heavy fragrance is the first thing to avoid. Beard hair holds scent far longer than skin does, and a strongly perfumed bar will linger through the day in a way you may not have chosen. A moderate fragrance is more forgiving, present at the wash, faint by midday.
Highly alkaline, harsh soaps are the second. They cut oil efficiently and leave the skin underneath tight and the hair brittle. A properly cured cold-process bar is milder, since the curing time allows the soap to settle to a gentler pH.
The third is strong essential oils. Some people find concentrated essential oils irritating against facial skin, particularly the skin under a beard, which is warmer and less ventilated than the rest of the face. This is a matter of personal tolerance more than rule. The same caution that applies when scent returns to sensitive skin applies to a beard: introduce, observe, adjust.
Driftwood, sandalwood, cedarwood, and amber, sits well against beard hair for this reason. The woods are deep rather than sharp, the fragrance moderate rather than insistent, and the cured bar is mild on the skin beneath.
After the wash
Soap cleans. It does not condition for long. A beard oil or balm worked through damp hair after washing handles the conditioning, softening the hair, settling the skin, and keeping the beard pliable between washes. The two are separate jobs. Wash to clean; condition after.