In the bowl of a stand mixer, or in a large bowl (if mixing by hand), stir together the water, sugar and yeast. Let sit until it starts to foam, 10 to 15 minutes.
Mix in 2 cups (280g) of the flour along with the melted butter and salt. If using a stand mixer, attach the dough hook and add the rest of the flour. If mixing by hand, use a sturdy spatula or wooden spoon until it’s too thick to stir, then scrape onto a lightly floured countertop.
Knead the dough for 3 to 5 minutes on medium-high speed until it forms a smooth ball. If the dough is not pulling away from the sides of the mixer bowl, add 1 tablespoon at a time, until it does. The dough should feel slightly sticky, but come away from the sides of the bowl. If kneading by hand, it should not stick to your hands. (I added 3 additional tablespoons to get it to the right consistency.)
Cover the dough in the bowl with a kitchen towel and let rise in a warm place until doubled, about 1 hour. (If kneading by hand, let it rise in a lightly oiled bowl.)
Preheat the oven to 450ºF (232ºC). Line two baking sheets with parchment paper or lightly oil them.
Bring the water, baking soda and syrup (or brown sugar) to a boil in a large, wide pot. It will foam up so make sure the sides are high enough to handle that.
On a lightly floured surface, divide the dough into 8 equal pieces. Roll each piece until they’re logs about 14-inches (35cm) long. Most likely the dough will be too elastic soon after you start rolling. So roll each one partially, then let them all relax for 5 minutes before you finish rolling them out.
Using a dough cutter or chef’s knife, cut the dough into 2-inch (5cm) pieces. When you have enough pieces, drop them into the boiling water. Cook for 1 minute, stirring the dough bits in the water very gently at the halfway mark, encouraging the bobbing doughs to get covered on both sides with the hot liquid.
While you are cooking the first batch of bites, start working on the other pieces of dough so they are ready to boil. The bites will come out better if the dough hasn’t had too much time to rise again.
Remove the first batch of boiled dough from the water with a mesh utensil to drain them a bit, and place them on the baking sheet, evenly spaced apart. (They won’t expand too much, so they can be as close as an inch, 3cm, apart.) Continue cutting and boiling the rest of the dough until the first baking sheet is full. I found I could boil about 20 at a time. (Note: They will not all look the same, or be perfect, which is fine.)
Sprinkle the pretzels with a bit of coarse sea salt and bake until deep golden brown, about 8 to 10 minutes, turning the baking sheet midway during baking. Baking times will vary so keep an eye on them and check at the 6 minute mark. The darker they are, the crispier they’ll be when they cool. Cool on a wire rack
Continue to cook the rest of the pretzel bite dough the same way.