Reading the ratio
80:20 means 80% coffee and 20% chicory by weight. 100% Coffee means no chicory has been added. That is the whole of it.
When a pack of South Indian filter coffee shows two numbers, they are the proportions of coffee to chicory. The declaration is required on the pack, so it is never something you have to guess at.
- 100% Coffee: coffee only, nothing added.
- 80:20: eighty parts coffee, twenty parts chicory.
- 70:30: seventy parts coffee, thirty parts chicory. More chicory-forward.
What chicory does in the cup
Chicory is not coffee and does not pretend to be. It brings colour, body and a distinct bitterness, and it holds up well against hot milk and sugar. Many people who grew up on filter coffee are, strictly speaking, used to the taste of a coffee and chicory blend rather than the taste of coffee alone.
A higher coffee percentage is not automatically a better cup. It is a different one.
Someone raised on 80:20 often finds 100% coffee thinner and sharper than they expected, because what they are missing is the chicory. That is preference, not quality.
Curious what this tastes like in the cup? See the coffees.