Why Is My Matcha Bitter? Fixing Bitter, Weak, Clumpy, Separating, Off-Colour and Flat Matcha Lattes (for Cafés)

Matcha lattes are a standard menu item at cafés in Singapore and Thailand. When we checked in October 2026, Starbucks Singapore’s official menu listed a Matcha Latte, an Iced Matcha Latte and a less sweet Iced Low-fat Matcha Latte (Less Sweet), and Café Amazon’s delivery menu in Thailand listed a Fresh Matcha Latte (เฟรชมัทฉะลาเต้) at 60 baht. With so few ingredients (matcha, water and milk), any inconsistency, such as bitterness, lumps, settling or a dull colour, goes straight to the customer’s eyes and tongue. This article checks the cause of each symptom against government and research sources and sets out fixes you can make in the café. For the recipes themselves, see How to Make a Hot Matcha Latte and How to Make an Iced Matcha Latte.

Quick diagnosis table

Most matcha latte problems come from one of five things: water temperature, the amount of matcha, how it is dissolved, the condition of the matcha, or milk temperature. Find your symptom in the table below and change one thing at a time, starting with “What to try first.”

Six symptoms at a glance

Symptom	Main causes	What to try first	Section
Bitter or astringent	Water too hot, too much matcha, second-flush or later matcha	Use water at 70 to 80°C	Bitter
Weak or watery	Matcha ratio too low, melting ice	Re-weigh the matcha in g and liquids in ml	Weak
Clumps	Not sifted, all the liquid added at once	Sift, then make a paste with a little hot water	Clumps
Settling or separating	Matcha floats rather than dissolves, large particles	Stir just before serving	Settling
Yellow, brown or dull colour	Heat, acid, light, old matcha	Check where the matcha is stored and when it was opened	Colour
Foam disappears quickly	Milk too hot, milk fat, coarse matcha	Heat milk to no more than 60°C	Foam

How to use the table

What follows is our own view. If two symptoms appear together, fix the one higher in the table first. For a latte that is bitter and dull, for example, first check whether the bitterness stays after lowering the water temperature, and if nothing changes, suspect the matcha itself. If you change two or more things at once, you cannot tell which one worked.

When your matcha latte is bitter

Bitterness and astringency come from catechins and caffeine, and with green tea brewed from leaves, more of them come out the hotter the water. Review water temperature, the amount of matcha, and the harvest of the matcha, in that order.

Water temperature changes which compounds come out

In a green tea feature in the magazine of Japan’s Ministry of Agriculture, Forestry and Fisheries (MAFF), the head of a regional branch of the Japanese Tea Instructor Association explains that theanine (an amino acid common in tea), the umami compound, comes out even at low temperatures of 50°C and above, while catechins and caffeine, the astringent and bitter compounds, come out at high temperatures of 80°C and above.

In MAFF’s research summary “Cold-brewed green tea,” brewing green tea with cold water at around 10°C, about refrigerator temperature, released theanine and EGC (epigallocatechin, a less astringent catechin) in amounts not much different from hot water, while caffeine, which is bitter, fell to about half, and EGCG (epigallocatechin gallate), which is astringent, fell to about one fifth.

Source: MAFF, “緑茶の美味しさと機能性を両立する『水出し緑茶』” (Cold-brewed green tea that combines flavour and function, in Japanese) https://www.maff.go.jp/j/kanbo/kihyo03/gityo/new_tech_cultivar/2021/2021seika-19.html

Both sources are about green tea brewed from leaves, not measurements of matcha, which is drunk as a whole powder. Even so, the Kyoto Prefectural Tea Research Institute advises dissolving matcha in water cooled to 70 to 80°C, and not using freshly boiled water applies to matcha as well.

Re-weigh the matcha

Ippodo Tea’s matcha latte recipe dissolves 3g of matcha in 100mL of 80°C water and adds 100mL of milk. A comparison with other official recipes is in How to Make a Hot Matcha Latte. If you measure by heaped spoonfuls, the amount of matcha varies from cup to cup, and some days the latte is bitter and some days it is not. Weigh matcha on a scale that reads to 0.1g and write it on the recipe card in grams.

Second-flush and later matcha is more bitter and astringent

Minamikyushu City in Kagoshima Prefecture explains that second-flush tea grows in a period with longer sunshine than first-flush tea, so it contains more catechins and caffeine, the bitter and astringent compounds, and less umami and sweetness. If the latte is still bitter after fixing temperature and amount, compare matcha from different harvests side by side with the same recipe. The difference between harvests and grades is in Matcha grades, and cold-whisking, which tastes less bitter, is in Clear Matcha.

When your matcha latte is weak or watery

If it tastes weak, either the share of matcha in the total liquid has dropped, or melting ice has added water. Check first whether milk was increased while the matcha stayed the same.

Look at the matcha ratio

Comparing official matcha latte recipes, matcha made up about 1.3 to 1.8% of the total liquid (our calculation in How to Make a Hot Matcha Latte). Ippodo Tea’s recipe is 3g of matcha in 200mL of water and milk combined, or 1.5%. When you use a larger cup or add more milk, increase the matcha in the same proportion.

Allow for ice in iced drinks

In iced drinks, the heat of matcha dissolved in hot water melts the ice and dilutes the drink. Using less water to dissolve it, dissolving it in cold water, or putting the same amount of ice in the glass every time will steady the taste (our view). How to pour two layers is in How to Make an Iced Matcha Latte, and what to do when oat milk dulls the flavour is in Oat Milk Matcha Latte.

When your matcha clumps

You can prevent clumps by sifting just before use and making a paste with a little hot water first. Clumps are not a quality problem, but they spoil the texture and the look.

Why clumps form

Marukyu Koyamaen says clumps can form in matcha from static electricity and vibration during shipping, and that they do not affect quality. Because they look bad and make matcha harder to whisk, it recommends sifting. What follows is our own view: keep spoons, strainers and bowls dry so no drops of water get into the powder.

Sift, then make a paste

The Kyoto Prefectural Tea Research Institute advises sifting matcha once through a tea strainer to remove clumps, pouring in a little hot water, dissolving it with a chasen (bamboo whisk) so no clumps form, and then pouring in the rest. Do not pour all the milk or water in at once; make a paste with a little first, then add the rest.

Setting up for busy hours (our view)

What follows is our own view. Before opening, sift a day’s worth of matcha through a strainer into a dry airtight container so you do not have to sift each cup when orders pile up. Use a container that blocks light. Detailed steps for preventing clumps are in the “How to prevent lumps” section of How to Make Matcha, and the difference when adding powder with a whisk or frother is in Matcha Cold Foam.

When your matcha settles or separates

Matcha does not dissolve in water. It stays as fine particles floating in the liquid. Over time it will settle at the bottom, so stir just before serving and choose finely ground matcha to slow it down.

Larger particles sink faster

A 2003 study on using matcha in processed foods lists its problems as poor suspension (how well the powder stays floating in liquid), colour deterioration and high cost. In this study, ordinary matcha particles averaged 11.5µm (micrometres, one thousandth of a millimetre) and finely ground matcha 3.2µm, and the finer matcha sank more slowly in water. It also notes that ordinary matcha particles range widely from 1 to 100µm.

A guide to judging matcha in the Japanese journal Tea Research Journal also says that whisked matcha is a suspension (a liquid with particles floating in it) whose particles settle over time, so when tasting it you scoop while stirring with a spoon.

Stir before serving

What follows is our own view. A pre-made matcha base has particles collected at the bottom of the pitcher, so stir it every time before pouring. For takeaway, add a straw or stirrer and tell customers on the menu or at the counter to stir before drinking. When you change the matcha you buy, compare how much settles in the glass when freshly made and after five minutes. How to show layers is in the “Separation, settling, and showing the layers” section of Matcha Lemonade, Tonic and Soda.

When your matcha looks yellow or brown

The green of matcha is the colour of chlorophyll. It changes with heat, acid, light and time, taking on a reddish or brownish tint. Separate whether the colour has faded in the powder or after the drink was made.

Acid changes chlorophyll

A 2022 study of chlorophyll in green teas states that pheophytin (chlorophyll that has lost its magnesium) forms easily from chlorophyll under acidic conditions, has a brownish colour and lowers the quality of the green. The same study reported that of the green teas examined, only matcha had a higher proportion of the green chlorophylls a and b themselves.

Combining matcha with acidic liquids such as lemonade or orange juice makes the green fade more easily. Guidance on acidity and serving methods that keep the colour is in Matcha Lemonade, Tonic and Soda. For strong heat, as in baking, see Matcha for Baking.

Light and temperature fade it from the powder stage

A 2013 report from the Mie Prefecture Industrial Research Institute describes matcha products as one of the most light-sensitive processed foods. In a test exposing matcha to about 5,000 lux of light for 3 to 8 hours, there was no difference in deterioration between fluorescent and LED light, and matcha left in a 70°C storage chamber showed about as much colour deterioration as matcha exposed to light.

The first page of the report states that matcha products are one of the most light-sensitive processed foods and that, in display cases, ultraviolet and infrared rays from fluorescent lights cause deterioration, discolouration and off-odours. The method section says samples were exposed to fluorescent and LED light at about 5,000 lux and a room temperature of 25°C.

Source: Mie Prefecture Industrial Research Institute, “LED技術を利用した抹茶の光劣化軽減に関する調査” (Investigation on reduction of photodeterioration of powdered green tea by LED light), Research Report No. 37 (2013, in Japanese) https://www.pref.mie.lg.jp/common/content/000172115.pdf

A 2002 study that stored raw matcha at different temperatures found that it kept its product characteristics for 24 weeks at 25°C or below, but at 37°C it reached its usable limit in 3 to 4 weeks. The loss of green closely matched the loss of chlorophyll a. Marukyu Koyamaen also says matcha turns reddish as it ages or deteriorates.

What to check in the café (our view)

What follows is our own view.

Write the opening date on the bag, and when the colour starts to fade, compare it with an unopened bag from the same lot
Do not keep matcha in a clear jar on the counter or next to the espresso machine
Keep pre-made base in a container that blocks light, and write the time it was made
Oat milk is beige, so the colour may come out differently from dairy milk even with the same amount of matcha (Oat Milk Matcha Latte)

Storage in hot countries, and how to decide how many days to use an opened bag within, are covered in Matcha Shelf Life.

When the foam disappears quickly

A matcha latte has two kinds of foam, milk foam and matcha foam, and what you fix depends on which one is disappearing. Milk foam changes with temperature and fat; matcha foam changes with particle fineness.

Heat milk to no more than 60°C

Espresso machine maker La Marzocco says that the hotter milk gets, the less sweet and less structurally sound it becomes, and that above 65°C (150°F) foam dissipates more quickly. For well-structured foam, it says to heat milk to no more than 60°C (140°F), which is about when the pitcher feels hot in your hand. Attach a thermometer to the pitcher and stop at the same temperature whoever is making the drink.

Protein that holds foam, fat that gets in the way

Milk proteins gather at the boundary between air and water and help stabilise foam (Sarkar and Singh, 2015). A study of milk foaming between 5 and 85°C (Kamath et al., 2008) found that skim milk foam was most stable at around 45°C, and that in whole milk the milk fat hindered foam formation and stability at 15 to 45°C. In homogenised milk (milk with its fat globules made smaller) and UHT (ultra-high-temperature) milk, this effect was smaller. A review of milk foaming (Huppertz, 2010) also says lipids can be detrimental to foam.

These studies looked at conditions for foaming milk, not at café matcha lattes. In the café, foam the brand of milk you actually use and compare how long the foam lasts. Plant-based milks vary by product, and La Marzocco says barista versions designed with steaming in mind can achieve great results.

Matcha foam depends on particle fineness

The guide to judging matcha in the Tea Research Journal says that fine, high-quality matcha produces fine foam that does not shrink much over time, while matcha with large particles foams poorly, and uneven, coarse foam shrinks quickly. If whisked matcha foam does not last, look at the matcha particles as well as how it is whisked. How to make foam for menus topped with cold foam is in Matcha Cold Foam.

Fixing it in the café, and what to check when buying

When fixing, measure amounts, temperatures and times first, then change one thing at a time and compare with a freshly made drink. If bitterness, colour or foam do not recover after fixing method and temperature, switch to a different matcha and compare.

The order to fix things in (our view)

What follows is our own view.

Write down your current recipe: matcha in g, water in ml and its temperature, milk in ml and its temperature, sweetener in g
Check with a scale and thermometer that drinks are made as written
Change only one “What to try first” item from the table, and taste it side by side with the drink before the change
Write the change and the date on the recipe card, and have everyone use the same card

How long a pre-made base or dissolved matcha can be kept, together with food safety guidance, is in the “Can you make it ahead?” section of How to Make an Iced Matcha Latte.

What to check when buying

When changing matcha, check the specification sheet for harvest, origin, particle size (if available), production date and best-before date. When it arrives, look at the colour and smell, then make a latte with your café’s milk using the same recipe and compare. How to compare samples and the signs of deteriorated matcha are in How to Judge Matcha Quality, and how to choose a grade suited to lattes is in How to Choose Matcha for Café Lattes. Omakase Matcha sells matcha bought from the regions of Uji, Yame, Shizuoka, Kagoshima and Miyazaki, and you can request up to three samples.

Cost per drink after the fix

The matcha cost per drink is the buying price per kg ÷ 1,000 × the grams used per drink. If you raise the matcha from 2.5g to 3g to fix a weak latte, the matcha cost goes up 1.2 times. Add milk, sweetener and cup costs to get the ingredient cost per drink. How the price per kg is set is in Why Is Matcha So Expensive?, and other matcha drinks are on the matcha drinks page.

Sources

Starbucks Singapore, “Beverages” https://www.starbucks.com.sg/menu/beverages
LINE MAN Wongnai, “Café Amazon” https://www.wongnai.com/delivery/businesses/577439iz/order
Ippodo Tea, “Matcha Latte” https://ippodotea.com/blogs/recipes-to-brew-japanese-tea/matcha-latte-recipe
Kyoto Prefectural Tea Research Institute, “お茶のおいしい入れ方抹茶” (How to prepare tea: matcha, in Japanese) https://www.pref.kyoto.jp/chaken/irekata_maccha.html
Marukyu Koyamaen, “抹茶について・お茶の保存方法” (About matcha and how to store tea, in Japanese) https://www.marukyu-koyamaen.co.jp/about-tea/know-matcha.html
MAFF, aff April 2017, “特集1 緑茶(4)” (Feature 1: Green tea, part 4, in Japanese) https://www.maff.go.jp/j/pr/aff/1704/spe1_04.html
MAFF, “緑茶の美味しさと機能性を両立する『水出し緑茶』” (Cold-brewed green tea that combines flavour and function, in Japanese) https://www.maff.go.jp/j/kanbo/kihyo03/gityo/new_tech_cultivar/2021/2021seika-19.html
Minamikyushu City, “二番茶・三番茶・四番茶・秋冬番茶” (Second, third, fourth and autumn-winter flush tea, in Japanese) https://www.city.minamikyushu.lg.jp/chirancha/ajiwau/chirancha_shurui/8903.html
Haraguchi, Imada, Sawamura, “Production and characterization of fine matcha for processed food,” Journal of the Japanese Society for Food Science and Technology 50(10) (2003) https://agris.fao.org/search/en/records/647242e92c1d629bc9792fac
Murakami Kosuke, “抹茶の審査について” (On judging matcha), Tea Research Journal No. 134 (2022, in Japanese) https://www.jstage.jst.go.jp/article/cha/2022/134/2022_31/_pdf
Herrera, Viera, Roca, “HPLC–MS2 Analysis of Chlorophylls in Green Teas Establishes Differences among Varieties,” Molecules 27(19) (2022) https://pmc.ncbi.nlm.nih.gov/articles/PMC9572584/
Sago Toru, Inoue Kouji, “LED技術を利用した抹茶の光劣化軽減に関する調査” (Investigation on reduction of photodeterioration of powdered green tea by LED light), Mie Prefecture Industrial Research Institute Research Report No. 37 (2013, in Japanese) https://www.pref.mie.lg.jp/common/content/000172115.pdf
Haraguchi Yasuhiro et al., “原料抹茶の保存条件が品質に与える影響” (Effect of storage conditions on the quality of raw matcha), Tea Research Journal No. 93 (2002, in Japanese) https://www.jstage.jst.go.jp/article/cha1953/2002/93/2002_93_1/_pdf
La Marzocco Home, “steaming milk on the linea mini” https://home.lamarzoccousa.com/steaming-milk-on-the-linea-mini/
Sarkar A, Singh H, “Emulsions and Foams Stabilised by Milk Proteins,” Advanced Dairy Chemistry 1B (2015) https://eprints.whiterose.ac.uk/id/eprint/92291/
Kamath S, Huppertz T, Houlihan AV, Deeth HC, “The influence of temperature on the foaming of milk,” International Dairy Journal 18 (2008) https://research.ucc.ie/en/publications/the-influence-of-temperature-on-the-foaming-of-milk/
Huppertz T, “Foaming properties of milk: A review of the influence of composition and processing,” International Journal of Dairy Technology 63(4) (2010) https://research.ucc.ie/en/publications/foaming-properties-of-milk-a-review-of-the-influence-of-compositi/

FAQ

QWhy is my matcha latte bitter?

AThe usual causes are water that is too hot, too much matcha, and the harvest or grade of the matcha. Japan's Ministry of Agriculture, Forestry and Fisheries (MAFF) magazine explains that theanine, the umami compound, comes out even at 50°C and above, while the bitter and astringent catechins and caffeine come out at high temperatures of 80°C and above. The Kyoto Prefectural Tea Research Institute recommends water cooled to 70 to 80°C.

QWhy does my matcha clump? Is it poor quality?

AAccording to Marukyu Koyamaen, clumps form from static electricity and vibration during shipping, and they do not affect quality. The Kyoto Prefectural Tea Research Institute advises sifting matcha once through a tea strainer to remove clumps, dissolving it first in a little hot water, and then pouring in the rest.

QWhy does matcha settle at the bottom of my latte?

ABecause matcha does not dissolve. It stays as fine particles floating in the liquid. A 2003 study reported that ordinary matcha particles averaged 11.5 µm and finely ground matcha 3.2 µm, and that the finer matcha sank more slowly in water. Stir before serving and give a straw or stirrer.

QWhy does my matcha look yellow or brown?

AThe green of matcha is the colour of chlorophyll, which changes with acid, heat, light and age. A 2022 study states that under acidic conditions chlorophyll easily turns into pheophytin, which has a brownish colour. The Mie Prefecture Industrial Research Institute describes matcha products as one of the most light-sensitive processed foods.

QWhy does the milk foam on my matcha latte disappear so fast?

AOverheating the milk is one cause. Espresso machine maker La Marzocco says foam dissipates more quickly above 65°C, and to heat milk to no more than 60°C for well-structured foam. A study of milk foaming found that the milk fat in whole milk hindered foam formation and stability at 15 to 45°C.