Ijen Crater is an active stratovolcano mountain which is located on the border between Banyuwangi regency and Bondowoso regency of East Java, Indonesia. It takes one hour from hustle and bustle of Banyuwangi city center. Mount Ijen has 2769 metres above sea level of height. But the crater has 2386 metres of sea level. Acidic crater lake filled with water with a pH ( Acidity level ) approaching 0.1. This water becomes acidic due to the interaction of ground seepage water, rainwater, and the hydrothermal system that lies beneath the surface of the crater. this water is very concentrated with the main composition of sulfate and chloride. There was once a pair of volcanologists from France named Katia and Maurice Krafft who measured the pH of the water in the middle of this lake by boat.
Ijen crater is 181.4 km far away from Bali. we can go there by car or joining tour and travel service or if we start our journey from Surabaya, we can go there by train from Gubeng railway station and stop at Banyuwangi Kota railway station. it takes 6 hours. After arriving at Banyuwangi we can rent a motorbike or just joining a private tour from travel services to reach the location. We also can find hotels close to the mountain. There is a camping area in Paltuding point ( Climbers permit point ) for the visitors who prefer adventure camping. Climbers permit point is open everyday at 3 a.m. The climbing route to the Ijen Volcano can be completed within two to three hours depending on how quickly you can haul yourself up the top of mountain. The path includes three kilometres uphill treks. we can see the blue fire before 5 a.m. This phenomenon can only be seen an hour after sunset and an hour before sunrise. The blue fire is formed when sulfur within the volcano breaches the surface, it can reach temperatures up to 600 C and therefore the sulfur immediately encounters lower temperatures and pressures at the surface which causes the sulfur right away ignite and erupt blue flames up to five metres into the air. As with every natural sighting, its height and intensity depends on various conditions and can not be predicted.
Unfortunately when I went there I could not find these phenomenon. But I can still enjoy the stunning view morning when the yellow sunlight shines on the surrounding mountain like mount Merapi, the sister of mount Ijen. The morning haze and the turquoise color of the crater. Last but not least we can find the oldest sulfur mining at the crater of Ijen. Some of miners sell beautiful handy craft from sulfur which you can buy and bring it home.