Bring the vinegar and water to a simmer in a small saucepan, over medium heat and add the garlic, peppercorns, bay leaf, salt and sugar. Simmer for 2 minutes.
Add the Cachaça, if using. Simmer for 1 minute.
Pour this pickling brine over the biquinhos in the jars. Wipe the rims and sides clean and seal the jars. Leave on the kitchen counter to come to room temperature, then store in the fridge.Leave at least 2 days for the flavours to develop and the peppers to soften slightly. Consume within a month.