110 grams sourdough starter (50:50 water:flour ratio)
165 grams water
330 grams bread flour (the stronger the better)
15 grams malt syrup
8 grams salt
1 heaping teaspoon malt syrup
Mix sourdough starter and water, then add salt and malt syrup and mix until dissolved. Add flour and mix until it comes together, and then briefly knead to create a homogenous dough. Leave to rest for half an hour in covered bowl, then knead again to form a smooth dough and leave for another half hour.
Cut into six pieces (ca. 105g each) and form into balls. Leave on the counter covered for 20 minutes (cover with towel). SLightly flatten each ball and pinch through the middle to form a hole, and carefully stratch hole to make an even round. Place in a deep baking tray that has the bottom covered with course semolina. Cover tray and refrigerate overnight.
The next day take the tray out and leave to warm to room temperature. Wait until the bagels have risen adequately. Hea ovenm to ca. 220C. Boil large pan of water (water needs to be at least 5cm deep, maybe 8cm ideally) and dissolve into the water a heaping teaspoon of malt syrup. Boil each bagel for a total of about 1 minute, slipping over halfway through. Remove onto a tea towel and place on a lined baking tray and coook for about 15 minutes (remove from oven when shiny and reasonably well browned).