In a small bowl, combine the lukewarm water and yeast. Mix well and leave to sit for 5 minutes to ensure the yeast is active. Bubbles should form at the top of the water. Combine the salt and sugar to the yeast water and mix well.
In a large bowl, combine the flour, yeast water and olive oil. Bring together with a wooden spoon. Begin to knead the dough in the bowl and once it starts to form a ball, take it out of the bowl and place onto a lightly floured wooden surface. Knead for 5 minutes until slightly smooth.
Drizzle a bowl with olive oil and place the dough into it. Cover with glad wrap or a damp tea towel and place into a warm spot. Leave to proof for 1 hour. The dough will double in size.
Preheat the oven to 200 degrees Celsius and bring a large pot of water with the bicarb soda to the boil.
Take the dough out of the bowl and place onto a lightly floured working surface. Lightly flour a dough cutter or shark knife and divide the dough into 8 parts. Take 1 part of the dough and roll into a ball by using a cupping motion with your hands. This step should be done on a work surface that has not been floured and can create lots of friction. Roll the ball out into a long sausage shape. Grab the ends of the dough and slap the dough onto the counter as though you are using a skipping rope. This will further lengthen the dough. It should be roughly 20 – 22 inches long. Be careful not to break the dough in this step. Form a circle with the dough and then twist the two ends together. Bring the twisted ends back towards yourself and apply some pressure to form a pretzel shape. Place the pretzel onto a pre-lined baking tray and leave to rest while you make the others.
Once all the pretzels have been shaped, drop 2 at a time into the bicarb soda bath for 30 seconds each. Remove from the bath with a slotted spoon and place back onto the pre-lined baking tray, leaving space around the pretzels as they will rise and expand when baked. Sprinkle it with flaky sea salt while the pretzels are still wet.
Bake for 12 – 14 minutes or until golden and brown. Remove from the oven and brush with melted butter.