Increasingly, producers tout whiskeys and other spirits as “non-chill filtered.” But how does chill filtration affect spirits? Is it really an undesirable thing?
What is chill filtration?
As part of the distillation process, most spirits, and aged spirits in particular, are filtered to remove sediment or other unwanted particles.
Chill filtration removes fatty acid esters (FAEs) and other chemical compounds that clump together to create a cloudiness or haze when a spirit is chilled. Flocculation, the technical term for that clumping, is sometimes referred to be experts as “floc.”
“All chill filtration means is whether the liquid is cold,” says Bradford Lawrence, a rye whiskey specialist with Beam Suntory. He worked with the Old Overholt brand as its straight and bottled-in-bond rye expressions were switched to non-chill filtration last year.
Rather than filter at room temperature, a spirit brought to the freezing temperature of water or lower causes FAEs to bind together. This makes the clumps larger and easier to filter out. The process yields a clearer, slightly lighter-bodied liquid.
Not all spirits respond to chill filtration, however. Those bottled at 53.5% alcohol by volume (107 proof) or higher won’t cloud at freezing temperatures, says Lawrence. As a result, many producers don’t use chill filtration for cask-strength or overproof spirits.
Chill filtration: pros and cons
“Filtration in any form is not a bad thing,” says Lawrence. “It’s one of those levers that can be pulled in order to make a liquid how you want it to taste.” He likens filtration to polishing a stone. “You’re able to take this rough stone and polish it so other, more nuanced flavors have an opportunity to shine.”
Some distilleries employ both methods. They may use chill filtration on flagship bottlings, but skip it for special editions if a richer profile is desired.
Though whiskey gets most of the attention when it comes to chill filtration, the non-chill filtered movement spans brandies, rums and even a handful of white spirits like gin.
Many experts say the big benefits of chill filtration are shelf stability, visual appeal and consistency.
Some countries have specific requirements about clarity in spirits, so producers with global distribution may use chill filtration with those markets in mind.
“Russia and Japan have strict rules around sedimentation,” says Lawrence. “If you see [sediment], it causes issues. Chill filtration keeps that floc and haze out of the product and ensures that it visually looks good.”
At Mount Gay Rum in Barbados, the core range of products employ chill filtration, while limited editions do not.
“We chill-filter the core range to ensure consistency from bottle to bottle wherever you are in the world,” says Trudiann Branker, the producer’s master blender. “For Mount Gay, we have an already established mouthfeel across our core range, and for us, it’s imperative that this remains consistent from master blender to master blender.”
Those that opt against chill filtration say that forgoing the technique yields a more expressive, flavorful spirit.
Jane Bowie, director of innovation at Maker’s Mark, has been creating special editions of the Kentucky Bourbon that focus on qualities contributed typically by the casks. Not using chill filtration helps play up those qualities, she says.
“Our first expression was all about the fruit and the heavy notes and the wood characteristics,” says Bowie. “Filtration will rip out a lot of that stuff.”
To leave the larger fat molecules also results in a heavier, more viscous texture, she says.
“The analogy I use is: I’m Southern. When my grandmother makes green beans with ham hocks, when it gets cold, you see all the fat [from] the ham hocks on the beans.”
Fat equals flavor, she says.
Distillers also liken the extra viscosity in such spirits to whole milk versus skim milk, or whiskey sours made using egg whites.
“Texture matters more than you think,” says Bowie. “It’s just as important as the flavor. It’s about the whole experience—the texture, the body, the finish.”
Branker says that spirits that don’t employ chill filtration can be singularly flavorful.
“Our limited-editions are meticulously designed to give the consumer and rum enthusiasts the essence of tasting our rum straight from the barrel,” she says. These consumers are accustomed to spirits that don’t use chill filtration and don’t balk at sediment at the bottom of a bottle, or swirling around as rum is poured. “[They] almost prefer it.”
Why the “non-chill filtered” hype?
To be clear, there’s nothing wrong with chill-filtered spirits. But bottlings without chill filtration have cachet right now.
Some experts say that it’s a reflection of broader food and drink trends.
“Like many other industries, people are looking for authenticity, be it farm-to-table dining or organic and biodynamic wines,” says Branker. “It’s clear that people are most interested in the provenance and terroir of a product, and sometimes that comes with a bit of extra sediment.”
In other words, the same demographic that loves natural wines, cloudy beers or rustic ciders is also likely to embrace floc in their whiskey.
“People want things in their natural state,” says Bowie. “We’re not scared of ugly vegetables anymore or hazy IPAs. People want the purest, rawest form of whiskeys they can get.”
Some brands also avoid chill filtration as a way to tell a story.
“There are brands wanting to have a historical nod, [to say a spirit is] rooted in an older process,” says Lawrence. “From a marketing angle, it’s something new and different, it differentiates the product on the shelf and creates intrigue.”
Still, some producers are baffled by the craze for haze.
“In 70 years, we’ve never commented on filtration,” says Bowie, of Maker’s Mark. “We never used chill filtration, but we never talked about it because people didn’t care. Now people care and talk about it. It’s a badge of honor.”