Frozen drinks have a long history but there’s a sweet spot in the science that takes them to another level. Jake O'Brien Murphy gets into the specifics.
The lengths we’ve gone to, throughout human history, to enjoy a frozen refreshment are preposterous. The nivaroli of Sicily would ascend Mount Etna, the Madonie and the Nebrodi in search of tightly compact snow. Faced with avalanches, crevasses and some of the stiffest nipples in antiquity, they persevered, packing their haul into strategically located pits. All for a yearround supply of granita! The heyday of the Nivaroli was between the 16th and 19th centuries, or roughly the time it takes to play a single game of test cricket.
Broadly speaking there are two branches of the Frozen Cocktail family tree. I’m disregarding gaudy nonsense like alcoholic ice pops and ice cream, being the weird second cousin at the family reunion that they are. The ones that smell like vape fluid and still poke people on Facebook.
First, you have the Blended Family – the primary mechanism of the blender has remained the same since Stephen Poplawski patented the design in 1922. Mechanical force is used to break down ice and mix ingredients. This is achieved by using high-speed blades to crush and shear ice into smaller pieces. It is a legal requirement that any blender used for commercial purposes must sound like a WW1 propeller plane.
The second branch is that of the Slush Machine, known alternatively as the Frozen Cocktail Machine and the Granita Machine. These are usually the size of a semi-detached house and are nothing if not temperamental, seemingly only working on the fickle whims of some malevolent imp. They function by a refrigerated bowl and a continuously rotating auger that keeps the mixture moving. The agitation breaks the mix up as water forms into small ice crystals. The remaining liquid becomes saturated with sugar, thus lowering its freezing point and preventing the entire mixture from solidifying. It’s called freezing point depression or, to the layman, mastering the elements and in our hubris laughing defiantly into the face of God.
Blenders have the advantage of convenience and are straightforward to use. The drinks they produce, when done properly, are excellent. Is there a finer thing than seeing the constituent ingredients of a Margarita blitzed into a typhoon, only to settle into a chubby mass of undulating loveliness? The knack is in understanding the ratios of ice to intermediate liquid. Alejandro Bolivar, head bartender of El Floridita in Havana, once told me that to make truly excellent blended drinks you have to pay attention to the motor’s sound and the mixture’s movement. What it was exactly I was meant to be listening and looking for I must have missed, but I can say the Daiquiris were coming thick and fast and were the best I’ve ever had.
Goldilocks zone
Slushies require nous and at least a remedial comprehension of some sciencey bits. FYI, there is a lot of conflicting literature and opinion. Simply, discounting all other considerations, you want your drinks to sit between 13 and 15 Brix and between 6% and 10% abv. Brix, pioneered by the unfortunately named Adolf Brix, is a measure of the amount of dissolved solids in a liquid. This is via its specific gravity and is used where cocktails are concerned to measure dissolved sugar. Blah, blah. Plainly, 1° Brix is 1g of sucrose in 100g of solution. That’s your Goldilocks zone. That’s where you’re getting frozen loveliness. A pubic hair’s width on either side of that and it’s limpid water. Where people often go wrong, when eyeballing it, is they assume that any acidulant will counteract the Brix level, due to how we perceive sweetness and the inaccurate structures by which we make drinks, eg one part sweet + one part sour = balance
Frozen drinks on both sides of the family tree are often considered straightforward variations of their parent drink, but that’s balderdash and piffle! They take on an entirely different silhouette. The joy of a frozen drink is twofold – concentration and texture. If balanced properly, the freezing process focuses flavours and they feel as vivid as primary colours. A champion example is the Frozen Negroni, which takes on a velveteen prickle, impossible to access otherwise. An exemplary frozen drink is as fine as powdered snow. It’s an indulgent, more immediate sensation of refreshment. They’re serious drinks, yes, but they bypass all of that in celebration of pure juvenile joy. This is why I watch Iain McPherson so feverishly. Not since Schwarzenegger’s Mr Freeze has the Iceman so spectacularly cometh.