For the beer queso; bring the beer to a boil in a pan set over a high heat. Turn the heat down and stir in the remaining ingredients. Pour into a 12 hole ice cube tray and leave to cool then place into the freezer for at least 4 hours.
For the dough; mix all the ingredients together in a large bowl until the dough is cohesive then turn out onto a floured work surface and knead until smooth. It should be slightly sticky, not too hard to handle. Cover the dough and let it prove for at least 30 minutes.
Preheat the oven to 200 C / 180 C fan. Lightly grease two baking sheets.
Prepare the water bath by combining the water, salt, and bicarb in a saucepan.
Gently deflate the dough on a lightly greased work surface, then divide it into 12 equal pieces.
Flatten each piece of dough into a rough circle, and place a piece of the frozen beer queso in the centre. Wrap the pretzel dough up and around the filling, pinching the ends and seam with your fingers. Transfer pretzels to the prepared pans, and cover while you bring the water bath to a boil.
Drop the pretzel bombs, six at a time, into the water bath. Cook for 30 seconds, then return them to the baking sheet (using a slotted spoon), and sprinkle with salt.
Bake the pretzel bites for 15 to 20 minutes, until they're a deep golden brown; be sure to rotate your pans halfway through the bake time to ensure even browning.
Remove the pretzel bites from the oven, and cool slightly before brushing with the melted butter and serving.