Wine on Tap is back, and the stainless steel "Sankey" keg
concept is spreading through the U.S. wine market.
From San Francisco to New York City and most major wine
sales centers in between, on-premise operators are installing
dedicated, quality draft wine systems to serve their customers
wine−by−the−glass and carafe from this reusable, well proven
Restaurants and wine bars are enjoying profit margins in excess
of 25% over and above that of bottled wine by selling Wine
on Tap. With virtually zero product waste over partial bottle
spoilage in traditional wine−by−the−glass programs, Wine on
Tap has many product quality benefits. Add to that, consumer
awareness of the environmental benefits of reusable stainless
steel kegs and thus reduced landfill and recycling center
overflow; you can see how, if properly executed by the wine and
hospitality industries, the Wine on Tap category will flourish in
the 21st century and beyond.
The Wine on Tap concept was first attempted in 1981 and
1982 and again in the late 1980's to early 1990's with marginal
success. Its previous failures in the U.S. market were due in
part to low quality wines dedicated to the bulk "jug" wine
category, ignorance and mistrust from the consumer regarding
wines packaged this way, as well as the lack of proper dispensing
technology, and infrastructure in the supply chain.
What insures its success this time around involves wine
processing, packaging and dispensing improvements; and
perhaps most importantly on the hunch that there has been an
evolution of the wine culture within the U.S. market. The U.S.
wine drinker now understands that wine is not drunk only on
special occasions, but as a beverage to be enjoyed socially and
on a daily basis with meals. Wine need not be approached with
reverence and pretense, but simply drunk and enjoyed. How
it may be packaged is less important than if it is good quality,
tastes good and is reasonably priced.
Furthermore, the technological advances made in processing,
packaging and dispensing wines to be served on tap allow
us in the wine industry to deliver wines of better quality
and uncompromised integrity to this new and open minded
If you agree that the stage is set - that the consumer is now
willing to support alternative packaging of wine including wines
packaged in bulk for service on tap, then let's address some key components that will insure product quality from the wine keg
to this new consumer's glass.
Sankey Keg Washing, Sanitizing, and Filling
We've all seen kegs around the cellar at the winery, they're
commonly used for "breakdown," when quantities of wine less
than a full barrel are held and used for topping off other barrels
or small tanks. It makes sense that these same kegs can be used
for serving wine in your tasting room or a favorite wine bar or
restaurant. The kegs can be pressurized with nitrogen or argon,
and dispensed from a stainless steel tap similar to draft beer.
Then you can rewash the kegs at the winery, refill them and
send them back to the restaurant, right? Not exactly, selling
your wines this way will in the long term damage your hard
earned reputation in the market as well as affect the sales of
your cased goods.
Any good cellar hand can − along with a simple keg valve
dispense coupler modified with Tri Clover fittings, hoses and
a pump − wash and fill kegs at the winery. But would you send
your wines out into the market in recycled bottles that were
used over and over, and then filled by hand under less than
sanitary conditions? Probably not, so why send those same
wines into the market packaged in kegs that way?
Washing, sanitizing and filling kegs properly is one of the
keys to maintaining the integrity of your wines in the Wine
on Tap category. Quality control standards are just as exacting
as those on a commercial bottling line; good standards are in
place, thanks to the brewing industry. Kegs and their washing,
sanitizing and filling systems have been designed together
to ensure consistent, repeatable and effective results. Beer,
by nature is more susceptible to spoilage than is wine, so by
utilizing their sanitary protocol we can expect to achieve a
high degree of successful packaging of our wines in kegs. IDD
Processing and Packaging, located in Moorpark, California
designs and builds state−of−the−art winery and brewery keg
systems and along with N2 Wines of St. Helena, California are
leaders in the burgeoning Wine on Tap movement.
Inside a keg, there is a stainless steel spear (dispense) tube,
which delivers the product through the keg valve. It is also
used during the washing and sanitizing phases of the keg. The
tolerances of this spear and valve were designed to accommodate
specific pressures, flows, volumes and wash solution viscosities
in order to provide a thorough wash pattern over the interior
surfaces of the keg and the outer surface of the spear tube.
These precise operations can't be duplicated accurately by a
simple dispense coupler and a pump − specialized equipment is
used to wash and sanitize kegs fitted with a Sankey valve.
Once the keg has been washed, it is sanitized. Steam was used
for sanitizing in the brewing industry until the early 1990's when
the introduction of new direct food contact sanitizing products
like Oxine® replaced it – minimizing occupational hazards
and damage to rubber gaskets and o–rings in the kegs. The
same design properties of the keg, spear, valve, water flow and
pressures are utilized during sanitation, to sanitize the interior
of the keg and its valve and spear tube. To confirm successful
cleaning and sanitation of the keg and the correct functionality
of the keg washing and sanitizing system, well tried and proven
QA/QC Procedures* may be randomly carried out and spears
may be occasionally removed and swabbed. After complete
washing and sanitizing, the keg is purged with a sterile, filtered
inert gas, counter pressurized, and is then ready to fill.
Aseptic filling ensures spoilage organisms cannot enter the
product fill phase. When a keg is connected for aseptic filling,
the exterior of the valve is sanitized prior to engaging and
introduction of product. The clean and sterile keg is purged
(evacuated) of air and counter pressurized, so wine enters
the keg under a controlled filling speed without splashing or
foaming; the product flow is shut off at a predetermined volume
in the keg.
This method ensures that the keg is clean and sanitary - prior to
filling and the wine that goes into the keg is free of contaminants
that could affect the integrity and shelf life of your product in
Dispensing Wine on Tap at the Restaurant or Bar
So much of the success of the Wine on Tap category depends
upon the on-premise operator, yet he may not be aware of the
simple, but important concepts necessary to serve wine properly
this way. Regardless of the attempt made by the wine maker to
insure that his wine is prepped right, and packaged into clean
and sanitized cooperage, it is all for naught if that wine is served
from a poorly designed tap system.
The on-premise tap system requirements are simple, relatively
inexpensive, and critical to maintaining the quality of wine
served from the tap. The basic requirements are: 304 stainless
components (valve coupler, tubing nipples, and faucet), oxygen
barrier tubing, and a blend of inert gas containing nitrogen or
argon combined with carbon dioxide to push the wine through
Burgstahler Machine Works, in St. Helena, CA builds custom
taps from 304 stainless steel for dispensing wine and beer. Micro
Matic USA, Inc. distributes oxygen barrier tubing for wine,
as well as 304 stainless steel tubing connectors and couplers.
Type 304 stainless steel does not react negatively in the low
pH environment of wines, and is the standard material used in
winery fittings, tanks and kegs.
Oxygen barrier tubing with an EVOH layer is critical to
dispensing Wine on Tap correctly, as several feet of tubing may
lie between the keg and faucet. Polypropylene or vinyl tubing
is microscopically porous, and as a result allows oxygen into
the wine. Oxidation can occur within hours of wine contained
inside poly or vinyl tubing.
One of the most important and sadly, most overlooked
requirements of a proper wine system is the presence of
carbon dioxide in the gas blend. After fermentation, wine
is supersaturated with CO2 and other gases. During the
aging process, these gases, along with sulfur dioxide provide
protection against oxidation in the wine. Eventually most of the
gas dissipates, but a portion of the gas remains in the wine giving
it important sensory characteristics. When commercial wines are
bottled or packaged, they are done so with a carefully determined
amount of dissolved CO2 left in the wine, or adjusted to a level
stipulated by the wine maker. Dissolved CO2 in wine doesn't
mean the wine is carbonated, we're talking about concentrations
in the neighborhood of 400 ppm (parts per million) to 1,200
ppm. Wine doesn't seem "spritzy" below about 4,000 ppm, and
Champagne is often around 7,500 ppm dissolved CO2. What
the dissolved gas does in still wine is give it liveliness on the
palate, and it helps to elevate the aromatics. Dissolved gas is an
important component of a well balanced wine.
Wine on Tap systems that use pure nitrogen or pure argon are
not ideal for dispensing wine. There must be a percentage of
CO2 gas mixed with N2 or Ar to maintain the dissolved CO2
in the wine. This is especially important when dispensing red
wines, because at warmer temperatures the gas in the wine
comes out of solution faster. A red wine that loses its CO2 can
taste tannic and woody—it loses its fruit and aromatics. While
this does happen in white wine, usually they are held and served
colder and the gas tends to stay in the wine better.
In a partial keg, the head space is filled with gases among which
are N2 and CO2. When the head space of the keg contains pure
nitrogen, Dalton's Law of Partial Pressures contends that only
the N2 will be held in solution in the wine. The dissolved CO2
will "boil" out of the wine and into the head space, causing a
loss of dissolved CO2 in the wine that remains in the keg. A
Wine on Tap system which incorporates a blend of inert gases
containing CO2 will maintain that gas in the wine.
How much CO2 should be used in the dispensing gas? It
depends on the temperature of the wine and the pressure of
the gas within the keg. Since we're dispensing wine under
relatively low pressures, and assuming that the wines will not
be served above 60˚F, a readily available premixed gas of 75%
N2 and 25% CO2 works pretty well (this premixed gas is often
used for Guinness and other nitrogenated ales). More elaborate
systems involve units like the McDantim gas blenders which
can be regulated so that the dissolved gases are optimized for
temperature and pressure of a specific Wine on Tap system.
In summary, if the wine industry packages good quality wines
in properly washed and sanitized stainless steel kegs, and the
on-premise operator sells that wine using a quality standardized
dispensing system to an open minded consumer who wishes
to drink good wine every day at a great price – we've got a
legitimate wine category with a long and sustainable future.
Jim Neal, President/CEO − N2 WINES & Jeff Gunn, President/CEO − IDD Process & Packaging, Inc.