Place the water in a glass or ceramic bowl. Add the sugar, stir to mix, and then add the yeast and mix.
Add the flour and mix everything until you have a homogenous mass. Cover the bowl with a dishcloth or kitchen towel.
You will see the yeast go to work almost immediately as the mixture will start to bubble. Set it aside for three to five days, after which you can refrigerate it.
Stir the starter once daily because the mixture will separate. Eventually, you will see that the liquid that separates to the top is a dark brown.
This does not mean your starter is spoilt. It is an alcoholic liquid created by the yeast, and it helps produce that great tangy flavour of sourdough. Just mix it back into the dough. If you want your starter to have less of an alcoholic tang, pour off some of the liquid.
Refrigerate your starter. Each time you need to use some of it, replenish the starter with the same amount you remove.
For the pretzels:
Place all the ingredients in a bowl and, using your hand or a stand mixer, mix well. Knead the dough until it has a smooth consistency and can be formed into a round ball. It should not be too stiff- if that is the case, add a little water, a tiny bit at a time.
Place the ball of dough in a lightly greased bowl, turning over once to coat, cover with a kitchen towel or plastic wrap, and set aside in a warm place for about 45 minutes. The dough will rise a little.
Place the dough on a lightly greased surface and fold a few times to deflate the air. Form into a rectangle, and then divide into 12 equal parts.
Take one part and cover the rest with a kitchen towel to keep them from drying. Roll the dough into a ball and then into a rope, tapering the ends. You want a rope around 18 inches in length. If you encounter resistance, shape the rope to about half the desired length, set aside, shape the remaining balls of dough into half-ropes, and then go back to the first one and continue. This will allow the dough to relax, making it easier to shape.
Take the ends of the rope and criss-cross them to make a loop. Twist one more time if you want an extra-decorative pretzel, then bring the ends down and tuck them under the loop.
Place the pretzels, about 2 inches apart, on a parchment-lined or lightly greased cookie sheet.
Preheat the oven to 350 degrees. Brush the tops of the pretzels with some oil and sprinkle with coarse salt (you can brush the pretzels with some sugar and water mixed together for a darker colour, but I like my pretzels to be extra-salty and without any obvious sweetness).
Bake the pretzels for 25 minutes or until the tops are lightly golden-brown.