Hojicha Ingredients: What Roasting Does to Caffeine, Catechins, and Nutrition

Hojicha tastes mild. Roasty, smooth, low in bitterness — it feels like the gentler option on the shelf. But the chemistry tells a more complicated story. Roasting reduces some compounds and forms or increases others, including aroma compounds. The result is not a lesser green tea. It is a different tea, shaped by heat.

Here is what the roasting process actually does to the leaf — and what ends up in your cup.

Source: Japan Ministry of Education Standard Tables of Food Composition, 8th edition (MEXT) for the caffeine, tannin (polyphenols including catechins), and vitamin C rows. MEXT does not list pyrazines or melanoidin; their rows describe roasting products and do not compare measured amounts in Hojicha and Sencha. MEXT's infusion conditions are 15g of Hojicha in 650mL of water at 90°C for 30 seconds, and 10g of Sencha in 430mL of water at 90°C for 1 minute.

Compound	Hojicha (per 100mL)	Sencha (per 100mL)	What changes
Caffeine	~20mg	~20mg	Similar, despite the roasted taste
Tannins (polyphenols, including catechins)	~40mg	~70mg	Lower in Hojicha (infusion conditions also differ)
Pyrazines	Formed during roasting	Not compared	Created by Maillard reaction
Melanoidin	Brown Maillard reaction products	Not compared	A collective name for brown reaction products
Vitamin C	Trace (Tr)	~6mg	Infusion values, not roasting retention rates

What roasting does to the chemistry

High heat triggers the Maillard reaction — and that single event reshapes almost everything about the leaf. During the Hojicha roasting process, Sencha or Bancha leaves are exposed to high heat; a 1969 trial by Japan's national tea research station suggested that a roasting-drum wall temperature of about 160–180°C was suitable. At that range, amino acids and sugars begin reacting with each other rather than staying in their original forms.

The products of that reaction include melanoidin — a collective name for brown Maillard reaction products — and pyrazines, the family of molecules behind Hojicha's toasted, slightly nutty aroma. They are created by the heat itself.

At the same time, catechins begin to denature. Heat can isomerise and degrade catechins, changing their composition; a roasted stem tea study documented these changes. The vitamin C value for brewed Hojicha is a trace amount, not a measure of how much remains in the roasted leaf. The result is a leaf that has shed some of its green tea character and gained something new.

The key point: roasting is not subtraction alone. It is subtraction and addition happening at the same time.

Caffeine and catechins — what stays, what goes

Caffeine survives roasting far better than most people expect. Hojicha contains roughly 20mg of caffeine per 100mL — about the same as Sencha. Caffeine sublimes at 178°C; the upper end of the 160–180°C roasting-drum wall range the 1969 trial suggested was suitable is above that point, but the temperature alone cannot show how much caffeine is actually lost during roasting. The mellow taste is not a signal of low caffeine. Roasting changes the balance of aroma and taste; the mellow flavor alone does not measure any individual compound.

For anyone managing caffeine intake in the evening, that distinction matters. We have a dedicated article on caffeine in Hojicha with brewing variables and per-cup estimates. The short version: Hojicha is not caffeine-free, and it is not meaningfully lower in caffeine than standard Sencha.

Catechins tell the opposite story. Roasting reduces major catechins, with the changes depending on temperature and time. MEXT does not list catechins separately. It folds them into tannin, a broader polyphenol measure, which comes to about 40mg per 100mL in brewed Hojicha against roughly 70mg in Sencha. Those two figures also come from different infusion conditions (Hojicha: 15g of tea, 650mL at 90°C, 30 seconds; Sencha: 10g, 430mL at 90°C, 1 minute), so the numerical difference cannot be attributed to roasting alone. Less astringency, less of the sharp green note — all consistent with catechin loss. Hojicha still contains catechins, though roasting changes their composition; these chemical measurements do not establish antioxidant effects in people. Our ingredient guide to catechins in tea covers the broader picture, including how EGCG content compares across tea types.

The green tea ingredients overview is useful context here — it shows where Hojicha sits relative to the full spectrum of Japanese teas, not just Sencha.

Pyrazines, melanoidin, and the roasted aroma

Roasting forms pyrazines that contribute to Hojicha’s toasted-grain aroma. Pyrazines are a family of aroma compounds measured in roasted tea. They can form through the Maillard reaction when amino acids and sugars are heated.

In a study of 20 healthy adults who inhaled roasted green tea aroma, 2,3,5-trimethylpyrazine was described as the most important aroma component among the three pyrazines tested. The findings suggest that inhaling this aroma may have a calming effect on the autonomic nervous system, with less sympathetic and more parasympathetic activity.

Melanoidin is the other roasting product worth noting. The name covers a group of brown products formed through the Maillard reaction, rather than one compound. We can describe the amber color and rounded flavor of a cup without attributing them to melanoidin alone.

For more on how roasting shapes the aroma compounds in tea, including pyrazine chemistry across different tea types, that guide goes into the underlying mechanisms in more detail. The difference between Hojicha and Bancha is partly a roasting question — Bancha is the base leaf, Hojicha is what happens after the kiln.

Amino acids and vitamins — the nutrition picture

L-theanine is lower in Hojicha than in Sencha for two reasons. First, the Maillard reaction consumes amino acids during roasting — theanine participates in that chemistry and is partially broken down. Second, the starting leaf matters: analyses of commercial teas found lower total amino acid concentrations in Bancha and lower-grade Sencha than in Gyokuro and high-grade Sencha. That comparison concerns total amino acids, not a fixed theanine value for every product; it does not make high-grade Sencha a shade-grown category.

The umami quality is still present — a soft, slightly sweet undertone — but it is quieter than in an unroasted tea. Our ingredient article on theanine in tea covers how cultivation method, shading, and processing all affect the final amino acid content.

MEXT lists vitamin C in the Hojicha infusion as Tr, meaning a trace amount rather than an exact zero. Hojicha contains close to 0mg per 100mL, compared to roughly 6mg in Sencha. That gap is specific to Vitamin C — a heat-sensitive compound that begins degrading well below roasting temperatures. The MEXT food database also lists vitamin B2 at 0.02mg per 100g of Hojicha infusion; this is an infusion value, not a roasting retention rate. Comparisons between dry tea and an infusion need to account for the amount consumed. For an overview of vitamins in tea, including which survive brewing and which do not, that guide has the fuller picture.

We do not have a Hojicha-specific measurement here showing how roasting changes saponin content. Our saponin guide introduces this separate group of tea compounds.

The tea-type comparison in our Hojicha guide shows how these ingredient differences translate into the everyday cup — color and flavor.

For the full picture of what Hojicha's compounds do in the body, our article on Hojicha health benefits goes through the evidence.

A different kind of balance

Roasting asks the leaf to give something up. Catechins thin out. The infusion contains only a trace of vitamin C. The sharp, vegetal edge of fresh green tea softens away. Roasting also brings the toasted aroma of pyrazines and a different balance of flavor.

It is not a lesser tea. It is a tea built on different terms — subtraction and addition at the same time. If you want to explore that balance in the cup, our Hojicha offers its own expression of the chemistry described here.

References

• MEXT — Standard Tables of Food Composition in Japan (8th ed.) — caffeine and tannin values for brewed Hojicha and Sencha.
• Khan & Mukhtar (2013), Tea and Health: Studies in Humans, Current Pharmaceutical Design — a general review of tea and human health, not a primary study of Hojicha or antioxidant compensation by its roasting products.
• Sugimoto, Tatsumi & Ichitani (2025), Functional Foods in Health and Disease — study of how inhaling roasted green tea aroma and its pyrazines affected autonomic nervous activity and mood in healthy adults.
• Mizukami, Sawai & Yamaguchi (2008), Journal of Agricultural and Food Chemistry — study of how roasting temperature changes catechins and aroma compounds in Houjicha.
• Hara & Kubota (1969), Effects of Roasting Condition on the Qualities of Roasted Green Tea (Hojicha), 日本食品工業学会誌 16(4) — 1969 roasting-drum study suggesting suitable roasting conditions at a 160–180°C drum-wall temperature; the Mizukami, Sawai & Yamaguchi (2008) study listed above independently found desirable Hojicha flavor at 160°C for 30 minutes and 180°C for 15 minutes in preliminary sensory tests.