Hojicha – Evolving Taste Through Roasting

Following on from my Hojicha Honey Eggnog recipe, I thought it would only be right to devote a post to hojicha.

Hojicha is a Japanese roasted green tea, traditionally created by roasting bancha over charcoal. Bancha is a late-harvest green tea, consisting of coarser and larger leaves of the tea plant. Nowadays, large spinning drums and gas burners are used.

The Taste

I will try to keep my tasting concise by dividing it into 3 sections. First I’ll describe the tea leaves, then the brew, and lastly how I feel after drinking the tea, and any final thoughts.

The Leaves

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  • Appearance: Chestnut brown, small and fine twig-like leaves
  • Smell: Woody with hazelnut tones. A slight caramel note

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  • Wet Leaf Appearance: Brown and almost seaweed-like in appearance
  • Wet Leaf Smell: Sweeter than one would expect after smelling the dry leaf. It smells more all-rounded and softer

The Brew

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  • Appearance: A brown liquor with hints of red and amber
  • Taste: Roasted, nutty (a mix of hazelnuts and chestnuts in my opinion) with a slight caramel/vanilla aftertaste. Quenching and smooth, with very little dry or bitter aftertaste

The Verdict

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  • Soothing and relaxing. The perfect drink for winding down on a cold winter’s day.

The roasting process actually changes the aromatic profile of the tea, which is why hojicha tastes so different to what one would usually expect from a green tea. I did a bit of research into the science behind this flavour change, and would like to share my findings with you! Time to put the tea scientist safety goggles on…

Roasting on Taste

The components of tea can be identified by chromatography. Without going into too much detail, what this does is show you the building blocks of a substance. For example, using chromatography, you would find that green ink is made up of blue and yellow. Scientists in Japan have used this technique to find the chemical make up of hojicha before and after roasting.

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A chromatogram of green tea (above) versus hojicha (below) as produced by Yamanishi et al (1973).

As you can see, the chromatogram pattern has changed quite a bit before and after roasting!

If we take a closer look at what has changed, we can explain a lot of the differences in taste.

Hojicha has much lower tannin, caffeine and flavonoids levels than its unroasted counterpart. Tannins make a drink taste bitter and astringent (think wine). Caffeine and flavonoids are also said to stimulate ‘bitter taste receptors’ as you drink. This explains the bitter taste people associate with the popular high-in-caffeine beverage that is coffee. So put together, this trio contributes to the slightly bitter, vegetal and slightly astringent taste typical of green teas. As hojicha is lower in these substances, it makes sense that its flavour becomes more quenching, sweeter and subdued.

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Coffee tea or wine? Three very different drinks, connected by the science of taste.

Though the roasting process reduces the amounts of these substances, pre-roasted hojicha (i.e. bancha) is actually relatively low in caffeine to start with. This is because larger, older leaves tend to be used. As mentioned in my previous post, younger tea leaves contain more caffeine than older ones, so by drinking older tea leaves you are consuming less caffeine than you would if you drank young, early harvest pickings. Then again, the varietal of plant, shade growing, temperature of brewing and the final processed leaf shape can also affects caffeine levels (and thus we are reminded of the complex world behind the seemingly simple Camellia sinensis).

This brings me to the end of my first tea tasting post. I hope you found it interesting. I certainly found it fascinating to research the science behind how the taste of tea evolves through roasting – and yet I’ve only just touched the tip of the iceberg!

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