Place all the freshly scraped coconut into a big blender jar and add first only 400 milliliter water to the jar, the remaining water will be required for the second round.
Blend the whole content to a smooth milk.
Grab a big strainer and bowl and press the coconut mash so that all the juice falls into the bowl.
Take the coconut mash back to the blender jar and add now the remaining 100 milliliter of water and blend it once more just like the first time.
Strain again for the last time so that all the coconut milk is collected in the bowl and separated from the mash.
Discard the mash and either use the coconut milk or store it in a airtight bottle/container in the fridge.