Asam boi is the cocktail ingredient most Malaysians grew up eating but never thought of as cocktail-relevant. It is the dark, wrinkled, salty-sour preserved plum you bit into as a child, the one that came in a paper twist. In a cocktail, it provides an umami-sour layer that fresh lime cannot give you. A small amount goes a long way.
What it is
Asam boi is a preserved fruit: typically the Chinese plum (Prunus mume) or sometimes other Prunus species, salted, sun-dried, and sometimes brined with licorice and/or sugar. The processing dates back centuries in Chinese cuisine; it travelled to Southeast Asia with Hokkien and Cantonese diaspora.
In Malaysia, asam boi appears in dishes (curry, asam boi sauce for chicken), snacks (the paper-twist candy), and drinks (asam boi limau, the lime-and-preserved-plum cooler). Various spellings: asam boi (Malay), hum boi (Cantonese), li hing mui (Mandarin, also for the Hawaiian variant).
Flavour profile
Salty-sour-umami first, with a candy-sweet finish from the licorice and sugar in the brine. Earthy, slightly funky. The flavour profile is closer to umeboshi (the Japanese cousin) than to any Western preserved fruit.
Pairs naturally with tequila, mezcal, gin, dark rum, whisky, soju, and sake. Works well with lime, lemon, ginger, cucumber, chilli, and the bitter side of Campari and Cynar.
Where to source asam boi in Malaysia
Chinese groceries: any Chinese grocery in Malaysia stocks asam boi in 250g to 1kg packs. RM 8 to 18.
Supermarkets: Cold Storage, Jaya Grocer, Mydin carry asam boi in the Asian-snacks section.
Specialty grades: the higher-grade asam boi is darker, softer, and more umami-rich; the snack-grade is harder and more candy-sweet. For cocktails, the higher-grade gives more complexity.
How to prep asam boi for cocktails
Asam boi syrup (the standard). 200g asam boi, 300ml water, 200g sugar. Simmer 20 minutes, mashing the plums to release flavour. Cool. Strain through fine sieve. Keeps refrigerated 3 weeks. This is the cocktail-relevant prep.
Asam boi cordial. Variation of the syrup with added fresh lime juice (50ml per 250ml syrup) and a strip of lemon peel. Brighter, more cocktail-ready.
Asam boi infusion. 6 to 8 plums in 500ml tequila or vodka. Cap, leave 48 hours, strain. The spirit becomes salty-sour-umami; use in modified Margaritas or Bloody Marys.
Asam boi-salt rim. Crush asam boi (without the brine) with sea salt, 1:3 ratio. Use as a rim for Margarita variants.
Best cocktails with asam boi
Asam Boi Margarita: tequila, asam boi syrup, lime, triple sec, asam boi salt rim. The Malaysian-Mexican fusion.
Asam Boi Sour: whisky, asam boi syrup, fresh lime, egg white. The umami sour.
Asam Boi Highball: any base spirit, asam boi cordial, fresh lime, soda. Long and easy.
Asam Boi Bloody Mary: vodka, tomato juice, asam boi syrup (replacing Worcestershire), lime, celery salt, black pepper.
Asam Boi Negroni: gin, Campari, sweet vermouth, dash asam boi syrup. The salty-bitter twist.
Substitutions
- Umeboshi paste (Japanese) is the closest substitute, slightly more sour.
- Tamarind paste + salt approximates the sour-salty core.
- Salted preserved lemon for the salt-sour register.
- Worcestershire sauce + dash salt for the umami-salty depth.
Frequently asked questions
What does asam boi taste like in cocktails?
Asam boi is salty-sour-umami first, with a candy-sweet licorice finish from the brine. Earthy and slightly funky, the profile sits closer to Japanese umeboshi than to any Western preserved fruit. In cocktails it provides an umami-sour layer that fresh lime cannot give, especially in tequila, mezcal, gin, and whisky builds.
Where can I buy asam boi in Malaysia?
Every Chinese grocery in PJ and KL stocks asam boi in 250g to 1kg packs for RM 8 to 18. The Chinese medicinal-herb shops along Petaling Street, Pudu wet market, and the dried-goods stalls at Pasar Borong Selangor carry higher-grade darker asam boi. Cold Storage, Jaya Grocer, and Mydin also carry it in the Asian-snacks section.
What can I substitute for asam boi?
Umeboshi paste from Japanese groceries is the closest substitute, slightly more sour. Tamarind paste plus a pinch of salt approximates the sour-salty core. Salted preserved lemon works for the salt-sour register. Worcestershire sauce plus a dash of sea salt approximates the umami-salty depth in savoury builds.
Which cocktails use asam boi?
Asam Boi Margarita (tequila, asam boi syrup, lime, triple sec, asam boi salt rim), Asam Boi Sour (whisky, asam boi syrup, lime, egg white), Asam Boi Highball, Asam Boi Bloody Mary, and Asam Boi Negroni. At our bar, the Asam Boi Margarita is on the menu when asam boi is in season.
How long does asam boi keep?
Dry asam boi packets keep 12 months at room temperature, sealed. Once opened, transfer to an airtight jar; lasts 6 months. Asam boi syrup keeps 3 weeks refrigerated. Asam boi infusion in spirits is shelf-stable indefinitely once strained and bottled.