What you see: A wispy thing at the bottom of your honey liqueur
What it is: Clumping molecules! Known as “flocculation,” this can happen when organic materials find themselves in an acidic environment
Drink or toss: Decant the perfectly good liqueur into a different container, leaving the wispy bit behind. Then, sip away.
Caroline H., of Washington, DC made this liqueur herself. She added spices and honey to Everclear, boiled the mixture and then stashed her krupnikas until the time was right.
A couple of years went by. One day, she picked up the bottle and noticed a weird wisp at the bottom. She had expected the spices to settle out, but not to form this creepy shape. So, what’s going on?
Darcy S. O’Neil, the writer, chemist and “fizzisict” behind Art Of Drink, suspects we’re looking at a case of acid beverage flocculation.
Or, ABF, for short.
My new favorite word, flocculation, refers to the tendency of particles to clump together in something called, logically, a “floc.” The “floc” appears in a number of ways, including as sediment and a tuft-like wisp, as we’re seeing here. In some cases, flocculation is a good thing: the phenomenon is used by water treatment plants to pull out contaminants. Flocculation is also a critical part of brewing beer and making wine because it helps separate the yeast cells from the final product.
But, in other cases, flocculation is uninvited, such as in manufacturing soda with cane or beet sugar. A soft drink may look pristine when its first bottled, however, over long stretches of time, harmless, but unsightly impurities in the sugar can emerge and collect in visible clumps and tufts. Soda is acidic and this scenario brings us back to acid beverage flocculation.
Caroline's krupnikas certainly isn't soda. But it is acidic. Honey has an average ph of 3.9. In acid beverage flocculation, such acidity causes gradual clumping of organic materials. ABF is our likely culprit.
Unlikely to be a microorganism
Given that the honey liqueur looked fine for much of its life, that Caroline boiled it during production, that there were no unexpected bubbles (which could signal fermentation), no off smells, and that the wisp is on the bottom and not floating on the liqueur's surface, O’Neil concluded that the unexpected resident was unlikely to be a microorganism, but rather some harmless organic stuff. And while true conclusions are impossible without lab testing, the fact that the product in question has a high concentration of both alcohol and sugar would make it less friendly to microscopic invaders.
So, it’s likely that some component of the honey or the spices gradually responded to the acidic environment, coming together in this wispy way. It took so long because floccing compounds are only weakly attracted to each other. If they start out evenly dispersed, it just takes them a while to organize their floc parties.
A sour taste is a bad sign
One final thing to keep in mind: If the liqueur tastes sour, that could mean fermentation. When a preparation like this ferments, O’Neil notes, it’s best to toss it. That’s because without knowing what is causing the fermentation, it’s impossible to know whether the resulting product is safe. In this case, with no sour taste and no other evidence of fermentation, like an off smell or bubbles, such a scenario is unlikely.
With no off flavors, go ahead and drink!
Assuming no off flavors, and with the usual disclaimer that we're not doing any lab testing, Caroline should be able to decant the liqueur into another container and continue enjoying it. The decanting step is both for aesthetic and flavor reasons. If you were to drink some of that wispy clump, it could taste unpleasant.
BONUS CHALLENGE: Can you find the cheese hat in the photo above?
Darcy S. O’Neil. Chemist. Bartender. Writer at Art of Drink.com. Edye L.A. (2004) Sugar Quality in Soft Drink Manufacture: the Acid Beverage Floc Problem. In: Shahidi F., Spanier A.M., Ho CT., Braggins T. (eds) Quality of Fresh and Processed Foods. Advances in Experimental Medicine and Biology, vol 542.
K. Foong, K & Amal, Rose & Doherty, William & Edye, Les. (2002). A review on acid beverage floc. Zuckerindustrie. 127. 382-388. The Kinetics of Floc Formation in Acidic Beverages Produced from Cane Sugar.
Kevin K.W. Foong, B.E. PhD Thesis. University of New South Wales. School of Chemical Engineering and Industrial Chemistry. July 2003.
Drinking Water Treatment - Flocculation. Michigan Environmental Education Curriculum Drinking Water Treatment
Ph and acids in honey. National Honey Board.
Yeast flocculation: what brewers should know. K. J. Verstrepen, G. Derdelinckx, H. Verachtert, F. R. Delvaux. Applied Microbiology and Biotechnology (2003) 61:197–205.
Organic compounds of a feather flocculate together!