Brass is the number one reason blondes come back to my chair frustrated, usually convinced the color was done wrong. Almost always, it wasn't. Brass is what happens when the cool toner that finished your color fades and the warmth underneath surfaces — and in Chicago, hard water speeds the whole thing up. Here's what's actually going on, and how to slow it down.
What brass actually is
When we lift hair to blonde, we're removing dark pigment in stages. Underneath, every head of hair has warm pigment — gold, orange, red — and lifting exposes it. The final toner or gloss neutralizes that warmth into the cool, expensive-looking blonde you left with. Toner is not permanent. It fades over four to eight weeks, and as it fades, the warmth it was canceling comes back. That's brass. It's not damage and it's not a mistake — it's chemistry on a timer.
What speeds it up
- Chicago's hard water. This is the big one. Our tap water is loaded with minerals — iron especially — that oxidize on blonde hair and turn it orange. If your blonde went brassy fast right after moving buildings, the water is almost certainly why. (Full story in our hard water piece.)
- Hot water. Opens the cuticle and rinses toner out faster. Cooler showers, cooler final rinse.
- Sun and chlorine. Both oxidize blonde toward warm. A summer of pool days will pull you orange.
- The wrong shampoo. Stripping shampoos pull toner out a wash at a time.
How to actually fix it
At home, maintain — don't over-correct. A blonde-supportive shampoo like Heart of Glass Silkening, and purple shampoo once a week, three minutes, on damp hair if you actually see warmth. (Overdoing purple shampoo causes its own problems — I wrote a whole piece on that.)
Install a shower filter. In Chicago this is the single highest-impact thing you can do for blonde longevity. $40–$80, and it stops the mineral oxidation at the source.
Come in for a gloss. This is the real fix. A toning gloss every 6–8 weeks re-neutralizes the warmth evenly across all your hair — no lift, 30–45 minutes, and it resets the clock. Purple shampoo buys you time between glosses; it doesn't replace them. Blondes who keep a gloss cadence simply never look brassy.
When brass means something else
If your hair goes brassy within days of a fresh appointment, that's worth a conversation — it can mean the underlying pigment wasn't lifted far enough before toning, and the fix is a different approach next time, not more toner. Bring it back to us; that's exactly what the redo window is for.
