These are the real Bretzeln, not the crisp, bone-dry Pretzels you are given on an aeroplane. 

 

You need pure caustic soda for this. You can buy crystals of pure sodium hydroxide and make your own lye. Pure chemicals fit for use in food can be bought under the name Bretzellauge from a number of German suppliers online, for example. 

Don’t mess about with substitutes, such as dissolved bicarbonate of soda. It’s a very poor substitute. 

Make a 4% lye (4g pure sodium hydroxide crystals on one litre of water). You can store this in a glass bottle, as it can be reused many times. The lye shouldn’t be in contact with textiles, your eyes or any mucous membrane, but it is not very aggressive. A cheap pair of plastic gloves protect your hands, your reading glasses take care of your eyes. My worktop and my silicone baking sheets tolerate this lye with ease. 

For one full-sized baking tray (6 to 8 Bretzeln):

300g white wheat flour, 5g salt, 2 large nobs of soft butter, 20g fresh yeast (or dry yeast if you must), 90ml lukewarm water, 90ml lukewarm milk.

Knead thoroughly, then form a sausage from the dough with a 4cm diameter (just under 2 inches, if you are imperially inclined), then cut the sausage into 4cm slices. Now roll each chunk into a thinner sausage, approximately 80cm (3ft) long, and swiftly form into a Bretzel.

Line your baking tray with a silicone baking sheet (alternatively use baking parchment).

Gently pour the lye into a flat dish, such as a Pyrex baking dish. Put on the rubber gloves and dip each Bretzel into the lye. A simple in-and-out will do, the Bretzeln don’t need to rest in the lye. Take care as the lye makes them slippery, and makes them fall apart and the two ends of the dough sausage. 

Place the bretzels on the tray with a little space in between, and give them another 10 minutes to rise further. Sprinkle them lightly with coarse salt (rock salt, sea salt flakes, etc).

Return the remaining lye to the bottle, clean up, preheat the oven to 200C (390F). 

Bake for approximately 15 minutes, and enjoy as soon as you possibly can. They are best straight from the oven.