Ask Wine Wizard

The New Need For Sanitation



A note from the Wine Wizard: It’s very strange to be writing a part of this column with a note to all of you, rather than you writing to me. You should also know something else about me: I’m a likely coronavirus survivor. I say “likely” because, as of the time of writing (3/19/20) in Napa County, California where I live, there still are not enough tests to go around. So may I present some tips for all of us moving forward in this strange new world. As winemakers, we all have a bit of a head start in my opinion since proper cleaning and sanitation is (or should be) part of our routines already.


What’s the difference between cleaning and sanitizing?

Cleaning refers to the manual removal of dirt, soil, and grime on an item or a surface. Sanitizing is the next step, which, when done right, kills off the omnipresent germs such as viruses and bacteria. Spraying a surface with a diluted bleach solution (see below for the recipe) after you cleaned it and letting the bleach solution sit for a minute then rinsing or wiping it off, will santize. But a disinfectant sanitizer will not kill germs unless the surface has first been cleaned. Happily, mechanical scrubbing with soap and water does double-duty against coronavirus (SARS-CoV-2 virus that causes the COVID-19 disease) because the hydrophobic/hydrophilic nature of the virus particle means that it’s destroyed by the interaction with a detergent and water. This is why doctors recommend we wash our hands with soap and water for at least 20 seconds as much as we can . . . and the same reason we should always wash our winemaking equipment first before the sanitation step.

A disinfectant must have enough contact time, be used at the correct concentration, be applied to a clean, dry surface, and be appropriate against that particular organism. The CDC (Centers for Disease Control and Prevention) website ( has a lot of information detailing specific commercial and industrial chemicals and sanitizers that are approved for killing the SARS-CoV-2 virus and includes specific brand names, concentrations, and contact times.

How can I make my own sanitizing agents that are effective against SARS-coV-2?

The CDC says that if you’ve got household bleach (check the expiration date), isopropyl alcohol, or even good old 3% hydrogen peroxide in your medicine cabinet, you can make your own sanitizing solutions. I’ve made one of each kind, and put the solutions in clean, dry household spray bottles for easy application. I also bought about 40 washcloth-sized microfiber towels to use as washable wipes. Once you’ve used either a paper towel or a washable cloth to wipe a surface, assume that the towel’s got germs and viruses on it and either throw disposables away in a lined trash can or wash cloth rags immediately. Don’t forget to regularly sanitize your laundry baskets, or to launder their washable liners.

While sanitizing with spray solutions, it’s best to wear an N95 facemask if you have one, in order to protect your lungs from inhaling chemicals. If you don’t have an N95 mask, a scarf or bandana wrapped around your nose and mouth will still block larger droplets. Try to keep the area well ventilated so you’re diluting the amount of sanitizing solution that may reach the air around you. Regularly spray down high-traffic areas and surfaces such as switch plates, doorknobs, countertops, sink faucets, refrigerator door handles, and the door of the microwave. Over the year’s you’ve heard me ask you to “think like a microbe.” Now instead of wine invaders, we’re talking human invaders. Just like with winemaking, be sure to clearly label and date each spray bottle and keep out of reach of curious little kids. If you have older kids, rope them in on making these solutions and using them and you’ll cover a little math, chemistry, and P.E. all in one helpful homeschooling exercise!

Homemade sanitizing solutions against SARS-CoV-2:

• Bleach: 1⁄3-cup bleach to 1-gallon water (or 4 tsp. per quart of water) check expiration date, contact one minute.
– Only use bleach on surfaces that can handle it, i.e. it’s probably not best to use on fabrics, upholstery, or wood that you want to protect from bleaching.
– Don’t forget that bleach is a no-no in your cellar and around your winemaking equipment because the chlorine molecule could possibly contribute to a TCA (trichloroanisole) taint in your wine. Keep it reserved for your kitchen, bathrooms, and bedrooms . . . don’t get it near your winemaking equipment!

Alcohol (ethanol or isopropyl alcohol): The CDC recommends a minimum 60% for ethanol-based sanitizers and minimum 70% concentration for isopropyl-based, contact 30 seconds.
– Sadly, vodka and most commercial tipples are not strong enough to kill coronaviruses as they only clock in at about 40% ethanol. That said, Technical Editor Bob Peak adds “Since some states allow sale of Everclear or other neutral spirits at 190 proof (95% ABV), you could include a distilled-water dilution formula for those lucky residents of enlightened states. Using Pearson’s Square, I get that a 750 mL bottle of Everclear plus 438 mL of distilled water will land you at 60%. You can use it on things like wine thieves without the toxic (. . . er, as toxic) residue of isopropyl.”
– I use a 70% solution of isopropyl alcohol to sanitize my phone. Spray it on a microfiber cloth and wipe the phone and case with the damp cloth. Don’t saturate your phone or spray alcohol solution directly into the buttons or screen.

• 3% Hydrogen Peroxide: 3% is the usual concentration when sold in pharmacies and is effective with a 3-minute contact time, making it best for hard surfaces like stainless steel, tile, ceramics, and some plastics.
– Hydrogen peroxide loses its potency when exposed to air. Buy a new bottle after open for a while.

Can I use my winemaking sulfur dioxide solution or spray to kill SARS-CoV-2?

I did quite a bit of poking around on the internet and couldn’t find anything relating sulfur dioxide gas, potassium metabisulfite powder, or liquid SO2 solutions to combat SARS-CoV-2. Don’t forget that yeast and bacteria, which we’re always trying to control as winemakers, are living organisms and viruses technically are not. What may be useful against the former may not work on the latter; it’s safest to stay within the CDC’s guidelines for sanitizing solutions against the novel coronavirus. Please also remember that SO2 in any form is an inhalant hazard and can severely irritate lung tissue. If you’re suffering from COVID-19 or are recovering from it, you’re going to want to minimize your exposure to SO2 in any form and take extra precautions if using during your home winemaking activities.

What about a hand sanitizer, can I make my own?

While some health experts are in disagreement whether you should, there is no doubt that if done properly, it should effectively kill germs. The important thing is to make sure that you’re accurately measuring the ingredients and that you end up with about a 70% solution. Higher concentrations are not healthy for your hand’s skin and lower concentrations are not effective against the virus. WineMaker’s own Dave Green sent me his homemade hand sanitizer recipe:

–5 tablespoons of aloe vera to 1 cup 91% isopropyl alcohol. However, he did one better and broke out his scale so he knew exactly the amounts of his materials and could calculate a 70% solution: 2.4 oz. aloe to 8 oz. isopropyl alcohol. If you have a scale feel free to do this. If not, approximate measurements should work, but err on the high side of the equation for the alcohol concentration if anything.

But don’t forget good old soap and water can work even better and most doctors I’ve talked to would prefer us to wash our hands well at the sink with for 20 seconds or more instead of slathering on the hand sanitizer. Wash your hands when you can and reserve the hand sanitizer for those times you aren’t near soap and a sink.

My dearest, dearest readers . . . we’ve been together on this crazy home winemaking journey for more years than I can count (OK, since 1998 to be exact . . . I think). I’ve been so honored that you’ve trusted me to impart what I hope is wizardly advice for your winemaking questions and I’ll be thrilled if any of the above helps keep you or your families safer and healthier during this protracted germy “bad guy bug” phase in our lives. We got this WineMaker readers. Over and out, from your loving (and sanitized!) Wine Wizard.