Page 18 - Grapevine SeptOct 2021

In The Winery

gallon it will cost a winery roughly $2.55, in distilled death of the microorganism.
water costs, to achieve sterility before bottling.
High pH Cleaners
Physical Cleanliness
High pH cleaners will give the water a slick feel-
While pursuing a Food Science Degree, one will ing. This is the action of the lowering of the surface
study sanitation in great depth. From this we learn tension making the water seem soapy. Common
that a physically dirty surface cannot be sanitized examples of high ph cleaners are: TSP (tri-sodium
with sanitizing agents. To understand this, we must phosphate); soda ash (sodium carbonate); NaOH
understand that a sanitizer reacts on the surface (sodium hydroxide). High pH cleaners will also kill
with whatever it comes into contact. certain bacteria by disrupting the bacteria’s cell
wall. Once the cell wall is disrupted the bacteria
Let’s assume one has cleaned a surface but left may die. As mentioned earlier, if using a high pH
behind some dirt that has remained on the surface. cleaner always rinse the same surfaces that came
While one may achieve a brief moment of cleanli- in contact with the high pH cleaner with a low pH
ness using a sanitizing agent, it is not properly pre- cleaner. This will prevent any of the unwanted
pared to receive a grape juice or wine product. The cleaning agents from being introduced into the
sanitized microbes will slough off the surface of the wine. A common low pH rinse for this application
viable bacteria and expose living bacteria ready to is a solution of citric acid and water. Be sure to
grow! For this reason we want to remove all physi- rinse the citric from the same surfaces with just
cal dirt before using a sanitizer. water after using that formulation.
Low pH cleaner
It is also for this reason that stainless steel has
become such a large part of our storage vessels for A low ph cleaner will also penetrate the cell wall
wineries. Stainless steel is easily cleaned physically of some bacteria causing them to die. This action
and it holds up to chemical cleaners. For this rea- happens at approximately a pH of 2.6. Very few
son – please clean your tanks and enjoy the beau- low pH cleaners are used in the wine industry
ties of stainless steel. except to rinse away the high pH cleaner, usual-
ly with citric acid as mentioned in the paragraph
Chemical Cleanliness above. Larger wineries may use a phosphoric acid
solution for its low pH microbe killing power.
Many chemicals come to mind when we want to
clean. Be careful to select the proper chemicals. Ozone

Do not use soaps or detergents. Although they Ozone, a strong oxidizer, has strong killing power
are great surfactants [lowers the surface tension of when used properly. Many vintners find it helpful
water], they are very difficult to rinse from surfaces when using it with barrels that have had a micro-
due to how they lower the surface tension of the bial infection. Most agree that once a barrel has a
water and often residuals remain. These residu- spoilage microbe inside, it is difficult to completely
als can cause problems in wines and their flavors. remove or kill the microbes beneath the surface of
Below are the categories of chemicals that are the wood cells. Ozone is very effective in killing all
largely used in the wine business in no particular microbes when it contacts the microbe. Research
order. and be very careful with Ozone use safety wise.

Sulfur Dioxide
Quaternary Ammonium
Commonly used in the wine cellar as an every-
Quaternary Ammonium is used mostly to clean day tool, winemakers must realize this chemical
winery floors and walls although sometimes it is does little to sterilize and is limited in its sanitizing
used to clean tanks, hoses and equipment. Modern power. It should always be used in combination
formulations have made these noncorrosive and with citric acid, as a cleaning agent, since the lower
heat stable while attacking a very broad range of ph water will increase the effectiveness of the sul-
microbes via disrupting their cell wall resulting in fur dioxide thereby releasing more sulfur dioxide in

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