What Is the Lemon Test?
The lemon test is a simple, at-home method to check the authenticity and pH-sensitivity of natural dyes. By applying lemon juice (a mild acid) to naturally dyed fabric, you can observe colour shifts that reveal whether the dye is truly plant-based and mordanted correctly.
Why It Matters for Natural Dyes
Natural dyes derived from plants, minerals, and insects are pH-sensitive — meaning their colour changes in acidic or alkaline environments. Synthetic dyes, on the other hand, are largely pH-stable and won't react. This makes the lemon test a quick authenticity check for naturally dyed textiles.
How to Do the Lemon Test
- Prepare your fabric swatch — Use a small piece of your naturally dyed fabric.
- Apply fresh lemon juice — Squeeze a few drops directly onto the fabric.
- Observe the colour change — Watch for a shift in hue within 30–60 seconds.
- Neutralise with baking soda water — Apply a diluted baking soda solution to see the colour shift in the opposite direction.
- Rinse thoroughly — Rinse with plain water to restore the original colour.
What the Results Mean
Different natural dyes react differently to acid:
- Turmeric — Turns bright yellow to orange-red in acid.
- Indigo — Minimal colour change; indigo is relatively pH-stable.
- Madder — Shifts from warm red to a brighter, more orange tone.
- Pomegranate Rind (Yellow Dye) — Pomegranate rind yields a rich golden-yellow dye, quite different from the pink-red of the fruit's juice. When lemon juice is applied to pomegranate rind-dyed fabric, the yellow brightens and shifts toward a warmer, more luminous gold. This is because the tannins and flavonoids in the rind become more soluble and reactive in an acidic environment. With an alum mordant, the shift is subtle but clear — a deepening of the yellow with a slight greenish undertone. With an iron mordant, the acid can cause a noticeable darkening toward olive or khaki. The reaction is gentle compared to anthocyanin-based dyes, but unmistakably present.
- Henna — Deepens in acid environments.
Tips for Best Results
- Always test on a small swatch, not the full garment.
- Use freshly squeezed lemon juice — bottled juice may have additives that affect results.
- The intensity of the colour shift depends on the mordant used (alum, iron, copper).
- Iron mordants tend to darken colours; alum mordants give the clearest pH reactions.
The Lemon Test at Urlihouse
At Urlihouse, all our fabrics are dyed using traditional natural dye methods with plant-based pigments and eco-friendly mordants. We encourage our customers to try the lemon test — it's a beautiful reminder of the living, reactive nature of natural colour. Our dyes are honest, and they'll tell you so themselves.