It is absolutely critical to have good winery sanitation as dirty equipment does nothing but invite bad-guy bacteria and unwanted yeast beasties to munch on our wine. However — there is a point of diminishing returns where you can sanitize too much. I have seen some home winemakers get way too crazy with the microbe-killing, so let me share information with you that’ll allow you to make sanitizing decisions appropriate for your unique situation.
First of all, let me elaborate on three important vocabulary words we’ll use a lot when talking about getting our equipment scrubbed up and ready for good, clean winemaking. Winemakers often use the terms cleaning, sanitizing and sterilizing interchangeably, which is a mistake. All three of these terms mean very different things.
Cleaning refers to the physical removal of visible soil, grunge, muck and mung. Usually done with scrub brushes, squeegees or a clean towel, cleaning often is just as simple as scrubbing down the grape reception hopper or sweeping the floor. Sanitizing means that you’re doing something to a surface or piece of equipment to reduce the microbial load to an acceptable level, a fancy way of saying that you’re killing spoilage microorganisms with heat or a chemical solution. Sterilizing is another step altogether, and one that goes beyond the scope of anything you or I could practically do in the winery environment. When something is sterilized, it means that it is completely free of bacteria or other microorganisms. Usually reserved for strict laboratory conditions and hospital surgical instruments, no winemaker ever tries to achieve a “sterile” wine cellar.
Why don’t wineries attempt to sterilize, you ask? The two reasons are that it is practically impossible and that it is not necessary. Due to its low pH and high alcohol content, most wines already have some natural resistance to spoilage organisms built in. As any disgruntled brewer will tell you, most bacteria and even some fungi aren’t that happy at wine pH’s (3.0–3.75) and are much happier thriving in a higher pH environment like that of beer (4.0–6.0) or water (7.0). That being said, there are some bad guys that do like hanging around in the environment wine can provide and for that reason it still is smart to practice a sensible cleaning and sanitizing program in your winery.
The first step is cleaning, or removing any visible soil, scale or detritus. This is because microbes living in hidden nooks and crannies and any sanitizing solution you subsequently apply will not penetrate effectively into these areas. Be careful to use only gentle plastic scrubby pads or brushes when cleaning soft stainless steel because it can scour and scratch easily. You can even use dishsoap to help you clean and soda ash can be a useful ally in helping you loosen up dirt and grunge. While some would argue that soap and soda ash help kill microbes, to really be clean and ready to make wine, you have to follow cleaning with some kind of sanitation.
The most common sanitizing solution used in small wineries is a strong sulfite solution, a recipe for which is as follows: Dissolve 3 grams potassium metabisulfite and 12 grams of citric acid in 1 gallon (3.8 L) of water. This will yield a roughly 500 ppm solution which is very effective in winery sanitiation because most wine spoilage microbes are sensitive to sulfur dioxide at concentrations as high as this — the acid essentially makes the sulfur dioxide more effective. Once a surface is physically clean, rinse with this sulfur/citric solution, leave it in contact for about 5–10 minutes and then rinse with clear water. Don’t let strong sulfite solutions be in contact with stainless steel, silicone or some plastic containers for very long as they can be damaged.
Other sanitizing weapons worth checking into include “E-San 205” and PeroxyClean™. E-San 205 is a quaternary germicide that cleans and sanitizes and, on previously cleaned surfaces, carries a D-2 USDA rating which means that it doesn’t need to be rinsed with water to be considered food safe. PeroxyClean™ is a white basic powder, much like soda ash, but that also produces hydrogen peroxide when mixed in water. Its basic nature helps dissolve soil and scale while the hydrogen peroxide acts as a strong oxidizer, killing microbes as it bubbles in vats, hoses and barrels. Its bubbling action makes it especially good for hard to scrub places like the inside of siphon hoses. Like soda ash, however, it does need an acid rinse in order to neutralize the surface.
So as to your simple question, when and how often to sanitize winemaking equipment — the answer will vary depending upon the kind of winemaking you do. My rule of thumb is to always clean and dry equipment that is going into long-term storage. Secondly, always clean and sanitize a piece of equipment before you use it. Always clean well, making sure no color remains, if you have to go from red to white wine processing with no other storage break.
As for continuous use, if a press is used for two days straight, pressing load after load of sweet Chardonnay juice, you might want to empty and break it down once a shift, sanitizing it well — making sure all detritus has been cleaned off — to make sure it’s not developing a heavy microbial load.
One thing that is absolutely critical is never to use household bleach, otherwise known as sodium hypochlorite. Many older home winemaking books and articles refer to bleach as the perfect cleaner and sanitizer. The fatal flaw with this logic is that chlorine bleach, or any chlorine-containing cleaner or sanitizer for that matter, can contribute to “corked” wines or TCA (trichloroanisole), a stinky, swampy off-character that can completely ruin a batch of wine.