Page 27 - Grapevine May-June 2020

Around The Vineyard
In The Winery

TOPPING GASES

By: Tom Payette, Winemaking Consultant
T here is no substitute for a full tank and this transfer into a tank. The next day I will top it again

article is not to suggest that using an inert
and then start that same tank of wine on a weekly
gas is the right thing to do. Avoid, when
at all possible, keeping wine in less than a full fixed topping schedule, Fridays, so that each tank gets
additional gas every week.
capacity tank with the minimal amount of surface
area possible. When one does find themselves in Why? The inert gas is to protect the wine from
the compromised situation of storing wine in a tank oxidation. The goal is to fill the headspace of the
that is not full – the following information will help tank with enough gas to dispel as much oxygen as
minimize degradation of your product. possible and to protect the wine from oxidation
and potentially more importantly, micro-aerophilic
When? Most winemakers typically only use pro- spoilage yeast and micro-organisms. This process
tective inert gases after the wine has fermented is a noted temporary protective step that should be
and less natural Carbon Dioxide bubbles are being corrected by filling the tanks as soon as possible.
given off. This is often after the first or second
racking after fermentation. In some cases, howev- Which inert gas? My preference is to use Carbon
er, especially with varietals of a high terpene load, Dioxide because the gas is very heavy, will lay nice-
contributing to the floral aroma and palate, wine- ly on the surface of the wine, and protect the wine.
makers may explore use of gases while handling Carbon dioxide is relatively inexpensive, easy to
juice at pressing and forward. obtain and use. Argon can be used with success
but the costs are near more than triple from the
Where? Many winemakers use an inert gas in gas company I polled. Nitrogen, due to its buoy-
the headspace of an unfilled fixed capacity tank. ancy and physical properties is my last choice as a
Typically after the transfer is made into the tank a topping gas in tanks. Nitrogen can be used at bot-
winemaker will layer an amount of gas, usually by tling with great success, however, so please do not
“gut feel”, into the headspace of the tank. I recom- confuse this statement.
mend having the gas flow from the cylinder with
the regulator set to mimic a soft whistle blow from Measurement
ones mouth. My estimate is it may be coming out
of the tube at near 1 mile per hour or slower. My Few winemakers actually measure the amount of
regime is to lower the tube off the regulator down the gas entering the tank outside of the crude mea-
to the surface of the wine and then raise the tube surement of the regulator and gut feel. Others will
to about one inch above the surface of the wine sometime use a match or form of flame and insert
and allow the gas to flow out slowly at that level. it into the headspace of the tank of wine (between
8 and 14% alcohol) to see if the flame dies out. An
How much? The amount of gas needed is depen- oxygen meter may be used also but most wine-
dent on the headspace one is trying to fill. Smaller makers will use this tool briefly to understand the
unfilled tanks will take less time and gas than larger effects of what they are doing and then the meter
tanks. One thing is certain, outside of cost, it would measurement looses its appeal due to time etc.
be rare to add too much inert gas to the tank head-
space. Try to run some calculations based on cubic Preferred Method of Carbon Dioxide Use
feet to determine what is best for your operation.
Dry ice bricks 7”L * 3”W * 2”D ( about the size
Frequency of Application of a common household building brick) is without
doubt the best method of carbon dioxide use I have
Often I will top a tank with carbon dioxide (my ever used. A special dry ice block maker can be
gas of choice – see below) just after completing the purchased making these bricks that weight about

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