Lemongrass should taste bright and clean, with a lemon-peel edge and no sharpness at the back. If yours is bitter, the lemongrass is probably fine — something in the brewing is off. There are four usual culprits.
1. You boiled it hard
This is the most common cause by a distance. A rolling boil batters the leaf and pulls out the coarse, woody compounds along with the aromatic ones. Lemongrass is fibrous, and fibre is where the bitterness lives.
Fix: take the water off the boil before it hits the leaf, or drop it to a bare simmer if you are making a pot. Water just off the boil is hot enough — there is nothing here that needs a hard boil to extract.
2. You left it too long
Unlike most flower infusions, lemongrass does keep getting stronger and eventually turns. Twenty minutes in the pot is not “extra flavour”, it is a different, harsher drink.
Fix: 5–8 minutes, then strain the leaf out. If you want it stronger, use more lemongrass rather than more time. Leaving the leaf sitting in the pot between cups is what turns the second cup bitter.
3. Too much leaf
Lemongrass is assertive. Because the dried pieces look bulky and light, it is easy to put in far more than you meant to by volume.
Fix: weigh it once so you know what it looks like. About 2–3g per 250ml cup is right. After a couple of brews you will recognise the amount by eye.
4. It is old, or it is dust
Lemongrass that has been ground fine, or stored badly, loses its bright citrus top note first — and what is left underneath is the woody part. So stale lemongrass does not just taste weaker, it tastes proportionally more bitter.
Fix: smell it. Good dried lemongrass smells sharply of lemon through an open jar. If it smells mostly of hay, no brewing adjustment will rescue it. Buy it in cut pieces rather than powder, and in amounts you will get through.
Two things that make it rounder
If you like lemongrass but find it a little austere even when brewed correctly, the traditional Thai answer is to soften it with something sweet and aromatic. Pandan is the classic partner — it fills in underneath the citrus and takes the edge off. That is exactly why we sell the two together as a lemongrass and pandan blend.
A single dried stevia leaf in the pot does the same job without sugar. Add it at the start, while the water is hot — stevia will not release anything into a cold or cooling brew.