What kind of pisco should I use?
Peruvian pisco is the traditional choice and either style works. Quebranta often drinks rounder and more mellow. Acholado (a blend) can be more aromatic, depending on the producer. Use what is available and decent. This cocktail shows off the spirit, so avoid anything that tastes harsh on its own.
If what you have access to is Chilean pisco, choose a high quality, unaged style and be ready to tweak sweetness and lime a touch. Different base and proof can shift the balance.
Is raw egg white safe?
There is always some risk with raw egg. For the safest route, use pasteurized egg whites from a carton. If you use a whole egg, use fresh, properly refrigerated eggs and a clean shell. If you are pregnant, immunocompromised, or serving someone who is, skip raw egg and use pasteurized whites or aquafaba.
Can I make it without egg white?
Yes. You will lose the classic texture, but you can still make a great sour. Shake pisco, lime, and syrup hard with ice, then strain and serve up in a coupe or over fresh ice in a rocks glass. For a little foam, use aquafaba (the liquid from a can of chickpeas), about 1/2 to 3/4 ounce per drink. Start at 1/2 ounce if you do not want to pour half the can into one cocktail.
Why is my foam thin or bubbly?
Usually it is one of three things: not enough dry shake time, old egg whites, or a weak second shake. Dry shake about 15 seconds, then shake with ice 10 to 12 seconds until the tin feels very cold. If you want extra fine foam, try a reverse dry shake: shake with ice first, strain out the ice, then dry shake again for 10 to 15 seconds.
Can I use bottled lime juice?
You can, but you will taste it. Fresh lime juice is the whole point here. One drink needs 1 ounce (30 ml), typically 1 to 2 limes depending on size and juiciness.
What are the bitters for?
They add a warm, spicy top note that makes the drink smell as good as it tastes. It is the finishing move. If you do not have Angostura, you can skip it, but I recommend grabbing a bottle when you can. If you can find Amargo Chuncho, that is the classic choice.