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Java’s Mt. Ijen: The Largest Acidic Lake In The World


Java’s Mt. Ijen: The Largest Acidic Lake In The World

When you reach the crater, you have reached a different world.

Mt. Ijen is a world hostile to all living things. It’s dead forest, it’s rocky, dry surface of the mountain and the foul stench that stings your nostrils at the bottom of the mountain don’t immediately scream tourist destination.

Even though the place is automatically unwelcoming – with its unnatural colours and offensive smells – the stunning views make the hike more than worth it….

Written by @karlamarias


The major attraction of the mountain is the milky blue crater lake – the largest acidic lake in the world. Blue fire seeps out of the cracks at the bottom of the crater.

Be warned! I wouldn’t recommend doing the walk down to the blue flames unless you are a very passionate photographer with a lot of hiking experience.


The reason being is the sulphur miners are not very happy about the tourists interrupting their strenuous work… their job is hard enough without being interrupted by wandering, pesky tourists.

Also, it can be really dangerous.


But if you are too curious and adventurous to miss out on the spectacular scenery, please go with a local guide and wear a gas mask! The sulphuric gas can be toxic in high quantities.

So if you are a passionate photographer, experienced traveller or clumsy tourist up for the challenge – you’ll be treated to flames up to 5 meters high due to high pressure forcing the gas out of the mountain.


Many pictures we took of the flames show the cooled – but still burning – liquid form of the sulphur. This is often wrongly described as blue “lava”.


Even though blue flames are a rare phenomenon, they often occur during volcanic eruptions. Sulphur can generally be found more often in volcanic craters than other minerals thanks to it’s low melting/evaporation point. This makes it reach the surface more often.


Most of the “Blue Lava” sulphur settles down on the side of the volcano, creating the yellow rings around the cracks within the crater walls.

There is an unavoidable humanitarian issue you encounter on Mt Ijen – the plight of the Indonesian workers mining the sulphur.


They risk there lives every day, marching up and down the steep crater with 70-80kg of the precious mineral on their shoulders. One wrong step with this weighty baggage, and it could easily be their last. The tough work and breathing in the toxic gas for 10 hours+ every single day is doing untold damage to the workers’ health and lifespan.


Typically for Indonesia, even in the most desolate of regions, there is an amazing spot to have a little breakfast – accompanied by warm smiles and unimaginable vistas.


Surprisingly for a volcano, it can get a bit chilly. The locals tend to light little fires – which we had to do to not freeze our butts off at breakfast! Always welcoming to the obvious outsiders, you should ask to join – you may end up making some new friends.

If you don’t want to walk down to the blue fire you don’t really need a guide. The 1-hour hike is easy enough to walk without guidance and there is only one way the whole time so it’s impossible to get lost. The entrance without a tour costs Rp.150k for foreign tourists and 10k for Indonesians.


A small hint: At the end of the path – between the last resting point and the top – you can find a small pathway. If you keep your eyes open, it leads to an amazing spot to take pictures at the opposite of the entrance to the blue fire.

More than worth it for the Gram…


You can follow Karla’s journey through Java and the rest of Indonesia on Instagram:


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