In a past life, I was a lab technician in a chemistry lab, where for four years I used a very small portion of the knowledge I gained from studying chemistry. I left that industry over a decade ago, but little habits have stayed with me, especially when it comes to glassware.
I love chemical glassware. I have an (admittedly horrible) Erlenmeyer flask tattoo on my lower back, and I tend to lean towards kitchen appliances that look like they belong in a lab. At school I never minded ‘doing the dishes’, ie splashing around in an acid bath while cleaning the cups, round bottoms and – yes – Erlenmeyer flasks of all the organic and inorganic material that stuck to their insides. After a cleansing dip in the acid bath and a neutralizing splash in the basic bath, I rinsed each piece of glass three times to remove the last bit from the baths.
The three rinses were not a personal affliction, but something everyone did, and something I was instructed to do when my fellow student, Trevor, first guided me through the dishwashing process. “Each rinse removes 90% of the residue,” he explains. “By the time you’ve done it three times, you’ve removed 99.9% of it.” That impressed me, and I’m still rinsing things—especially dusty drinking glasses—three times.
To confirm what Trevor told me 13 years ago, and to get a little geek, I went to the… Alconox website to see if they had any similar advice. (Alconox makes industrial cleaning products similar to, if not the same as, what we used in my graduate lab.) I was not disappointed:
Different washing procedures for college and university glassware that require three rinses (triple rinse). We are also aware of historical documents published by early participants in the use of detergents to clean laboratory glassware from laboratory glassware manufacturers who recommend three flushes… The logic behind a triple flush is that when filling and emptying a vessel three times with water, each time you dilute by 2 orders of magnitude. In theory you are allowed to leave 1% of the contents of the vat each time you empty it, so with each rinse there is a dilution of 1:100 with fresh rinse water. A triple rinse results in a 6 orders of magnitude reduction of such water soluble residues that could be present in the dirty wash solution.
Is this overkill for the glassware in your kitchen? Yes. I doubt you’re working with reagents or chemicals that pose a threat in the form of residue, but there are times when a triple rinse is warranted, such as when rinsing a wine glass or beer glass. In fact, beer snobs take the cleanliness of their glassware almost as seriously as chemists. “Beer Clean” is a whole thing – a dust-free, residue-free standard designed to ensure you get the best out of your beer. From CraftBeer.com:
A clean beer glass is free of impurities: leftover disinfectant, beer, dirt, food, detergent, grease, chap stic [sic], lipstick, lip balm, boogers, or anything else that would give the escaping CO2 a place to cling to. These areas of dirt act as germination sites, allowing bubbles to attach to and collect around the tip. Every time you pour a beer into a glass that is not free of impurities, you (or your customers) will quickly spot the hidden residue left behind on an apparently clean glass.
…The Brewers Association’s Draft beer quality manual (DBQM) describes that a clean beer glass is one that “forms a good head, allows lacing during consumption and never shows bubbles that stick to the side of the glass in the liquid beer.”
Bubbles sticking to the inside of a beer glass is the most obvious sign that a glass is not beer clean. I don’t care what causes those germs, but I don’t want to drink it, and neither do you.
Getting glasses “beer clean” (or wine clean, if you are a wine drinker), means washing them separately from your other dishes, letting them air dry so that no fluff or fibers are left in the glass, and rinsing them quickly before filling them with beer (or wine). How often you rinse is up to you, but I always go for three, to remove as many potential germination sites as I can (or at least 99.9% of them).