My matcha foams and then the foam collapses

In short

This is a different problem from matcha that will not foam at all. The foam formed, so the powder was suspended and the whisking worked; what failed was the foam’s stability, and that is governed by bubble size, water temperature and how much powder is holding the structure up.

Likely causes, in order

Most likely first. Answer the question under each one before moving on — several of these look alike in the cup and are told apart only by what was done to the leaf.

1. 1. Too little powder for the volume of water

   Leaf quantity

   Check: Are you using around 2 g to 60 or 70 ml, or has the water crept up towards a mug’s worth?

   Fix: A thin suspension makes large fragile bubbles that burst quickly. Weigh 2 g and hold the water to 60–70 ml; the same whisking then produces a finer, denser foam that stands.

2. 2. The whisking stopped at large bubbles rather than fine ones

   Technique

   Check: Is the foam made of visible bubbles you could count, or of a uniform microfoam?

   Fix: Whisk briskly in a W or M motion with the wrist rather than the arm, keeping the tines just off the base, then finish with a slow circle across the surface to break the large bubbles into small ones. Large bubbles always collapse first.

3. 3. Water too hot

   TemperatureInferred by TeaHQ, not established

   Check: Did the water come straight off the boil?

   Fix: Use water around 70–80 °C. Very hot water thins the suspension and the foam drains faster; it also drives the bitterness that usually accompanies this complaint.

4. 4. A splayed or stiff whisk with too few working tines

   Equipment

   Check: Do the inner tines still curl inward, or has the whisk opened out flat?

   Fix: Store the chasen tines-down on a ridged stand so it dries in shape. A whisk that has dried splayed moves less water per stroke and cannot produce microfoam however hard it is worked.

5. 5. Residual detergent or oil in the bowl

   Equipment

   Check: Was the bowl washed with detergent, or has it held anything with fat in it?

   Fix: Rinse the bowl with hot water only and dry it. A trace of oil or surfactant destabilises foam immediately, which is why the same matcha behaves differently in two bowls.

6. 6. The matcha is old and has lost the fine particle structure

   StorageInferred by TeaHQ, not established

   Check: Is the powder still bright green, and how long has the tin been open?

   Fix: Buy smaller tins and keep them sealed and cold. Older powder foams less and holds it less well, and no adjustment of technique compensates.

Tea types this applies to

• Green tea

Brewing methods this applies to

• Whisking (bowl-prepared powdered tea) — Powdered leaf suspended in water rather than steeped and strained — the only common preparation in which the leaf itself is consumed rather than discarded.

When this cannot be fixed

Foam cannot be restored once it has drained. Rewhisking a collapsed bowl produces a coarser, shorter-lived head than the first attempt, because the powder has begun to settle and the water has cooled.

Related problems

Sharing a cause category, a tea type or a brewing method with this one.

• My bamboo whisk is losing tines — Fine bamboo tines snap off during whisking and turn up in the bowl, and the whisk feels stiff and splayed.
• My matcha latte is lumpy and the powder sinks — Whisked straight into milk, the matcha forms lumps that will not break up, and within a minute a green layer has settled at the bottom of the glass.
• My matcha powder has gone dull green or khaki — The powder that was vivid green when the tin was opened is now olive, khaki or faintly brown, and the bowl looks muddy rather than bright.
• My matcha tastes harshly bitter — The bowl is sharp and drying rather than sweet and thick, and the bitterness stays after the drink is gone.
• My matcha will not mix into cold water — Whisked straight into cold water or ice, the powder stays in lumps, floats in rafts on the surface and sinks in clumps to the bottom.

Sources