WINEMAKER Octobe-November 2002

Wine Kits
Clear it up
Step by step, how to filter your wine by Tim Vandergrift

K
it wines are designed to pro- croscopic organisms that could restart
duce clear, stable wine in a Fermentation are removed, the amount
relatively short time, ferment- of preservatives can be reduced. For
ing to dryness and falling clear the purposes of this article, we won’t
with the winemaker only needing to be discussing sterile filtration. It isn’t
follow the instructions. One thing that necessary for kit wines.
can enhance your kit wine, however, is Filtering also pushes the wine along
filtering. This article will deal with the in its evolution. As wine ages, com-
practical concerns of filtering a kit wine pounds combine and settle out, leaving
with the three most popular machines sediment. This eventually leaves the
on the market: the hand-pump filter, the wine with a smooth, clean flavor. Be-
mini filter, and the larger “super” filter. cause filtration prevents the formation
Many readers will be familiar with of this sediment, it “force-ages” the
the filter models discussed here. There wine, which tastes smoother while still
are other models available, but they all young.
operate on the same basic principle: If your wine is very cloudy, a filter
they use a system to force wine through will clog too quickly to effectively
a set of cellulose pads, which retain clarify it. The large particles in a very
solid materials and allow clear wine to young or very cloudy wine block the
flow through. fIlter pads, causing the pressure inside
A word on cartridge filter systems: the filter plates to rise. This in turn
A decade of experimenting with them causes the wine to spray out the sides
in applications ranging from filter- of the filter and puts stress on the pump
ing a single 3-gallon batch to filtering and hoses. You can only filter a wine
300 12-gallon batches has lead me to that is nearly clear already. Before fil-
conclude that most hobbyists are bet- tering, your wine should have already
ter served with plate-and-frame filters. been filled and racked. Filtering is liter-
Cartridge filters do have one advantage ally the last thing you should do to your
over plate-and-frame filters , in that wine, just before you bottle.
it’s easier to do a sterile filtration with Successive filtering (filtering first
them, removing all yeast cells and bac- with coarse pads and moving on to fin-
teria from the wine. However, for most er pads) isn’t necessary with kit wines.
of us, sterile filtration is unnecessary, Kit wines have low levels of dissolved
and the kind of absolute micron-rated solids, so if you’ve followed the filling
cartridges necessary to achieve sterility instructions carefully, they will only
are relatively expensive. need that single pass through a filter to
be nicely polished.
Filtering is the last thing Your wine must be properly sulfited
you should do to your wine before it goes through the filter. There
Filtering clears wine by removing is a chance that filtering can introduce
fermentation debris and some of the oxygen into the wine, but the correct
yeast. This prevents the material from level of sulfite will prevent oxygen
breaking down during aging, which in from damaging the flavor and color.
turn increases the wine ‘s stability. The wine should be at 35- 50 ppm of
Stable wines are less likely to change free sulfur dioxide prior to filtering.
their appearance or taste with time. This is equivalent to about one-half
When a significant number of the mi- teaspoon of metabisulfite powder per
6 US gallons (3 grams per 23 liters). spaghetti, then the passages in the filter work it out as you go). Place one fil-
Note: This is the total amount of sulfite pads would, in relation, be bigger than ter pad, rough side up, onto the bottom
that the wine should have, so don’t add the Houston Astrodome. plate (the one with the bolts sticking up
an extra half-teaspoon to a kit that’s al- What actually happens inside the fil- out of it). Place the separator ring onto
ready been correctly processed! ter is this: proteins and yeast cells, sat- the pad, ensuring that the inlet port is
urated with color compounds, are cap- arranged opposite to the outlet port on
Which pads to use tured on the pads, staining them with the bottom plate. Place the second filter
Choosing the right pad is important: pigment. This isn’t color that would be pad onto the separator ring, rough side
too coarse will leave your wine cloudy, left in the wine; it’s already bound to facing down, and then put on the top
too fine will clog too quickly. Differ- a substance that isn’t going to stay in plate, making sure that the outlet port
ent suppliers have different names or suspension anyway. lines up with the one on the bottom
numeric designations for their pads, so Second, the terpenes and esters that plate. As assembled, it will look like
we’ll refer to them by the general des- give wine its delicate aroma are dis- this from the bottom up:
ignations of “coarse,” “medium” and turbed by the vigorous jostling of the
“fine.” filter. This causes some of them to Bottom plate
Coarse filter pads are too coarse for go into hiding, binding to other com- Pad
use with kit wines. The holes in the pounds, and reducing the aroma and Separator ring
pads are just too big to effectively re- flavor of the wine. This “filter shock” Pad
move any haze-causing particles, as doesn’t mean the wine is permanently Top plate
they’re intended for other applications. damaged. It will recover after a few
Medium pads are usually recom- weeks in the bottle, better than ever. The pads will have both rough sides
mended for red wines. After filtration, Can filtering harm wine? Sure, if the facing the middle of this stack.
wine will show a significant improve- sulfite levels are too low and the filter- 4. Slip the washers over the bolts and
ment in clarity and brightness. ing introduces enough oxygen to cause tighten the nuts down. Be careful to
Fine pads are usually used for white spoilage, or if the filter and all the hoses torque the nuts down opposite to one
wine, although they do a good job on and connectors are not absolutely sani- another, like tightening the bolts on a
reds as well. One pass through the pads tary. car engine, or on a wheel: If you tight-
will remove most of the yeast cells in
the wine and leave it sparkling clear. Using a hand-pump filter
They will clog up more quickly than 1. Sanitize all surfaces that will come
medium pads, but the measure of ef- in contact with the wine. Dip the fil-
ficiency of any filter pad is whether it ter plates in a sulfite solution (or use a
effectively retains the materials cloud- trigger spray bottle to coat them with
ing the wine, not how much wine will your sulfite solution). Circulate sulfite
go through it. through the pump reservoir and hoses.
Rinse all surfaces thoroughly.
Stripping wine 2. Soak your pads in a solution of
Some people worry that filtering one quart (one liter) of cold water with
will “strip” wine of color or flavor. an eighth of a teaspoon (0.75 gram) of
Consumers have been egged on to this metabisulfite and one teaspoon (3.5 g)
idea by marketing wonks touting unfil- of citric acid dissolved into it (see page
tered wines as superior products. While 55). If you don’t have any citric acid
there’s nothing wrong with unfiltered you can substitute two teaspoons of
wine, and if you try hard enough in lemon juice. Soak each pad in this solu-
a commercial winery you can actu- tion, allowing it to saturate. Some pads
ally over-filter wine, this doesn’t wash will take longer than others; when they
among home winemakers. There is cur- no longer float, they are fully saturated.
rently no home system available with Do not over-soak them.
filter pads fine enough to “strip” flavor, 3. Follow the instructions that come
color or aroma out of wine. with the filter for assembling the pads
Let’s think about wine going through into the plates. If your machine doesn’t
a filter. If we visualize a color or aroma have instructions, use the following
molecule as being the size of a piece of (some plate designs are different, so
en one too much before the others, you over-soak them. has to do.
could crack the plates. 3. Put the pads into the machine. The 3. The first half-quart (1;2 liter) of
5. Fill the tank with fresh, cold water, coarse side of the pads faces towards liquid that comes out of the filter will
about 2 gallons (7 liters). Connect the the incoming wine and the holes in the be the water used to rinse the pads and
outlet hose of the tank to the inlet port pads line up with the holes in the plates. should be discarded.
of the plate assembly (it’s on the sepa- 4. Once the pads are in and lined up 4. If you are filtering more than one
rator ring). Connect the outlet hoses to you can gently tighten the plate assem- kind of wine, don’t change the pads for
the ports on the top and bottom plates. bly. Over-tightening this will damage each batch. Instead, go on to the next
6. Screw the pump handle onto the the plate-frame unit, and may ruin the wine, but you should filter light whites
tank, place the plate assembly in a threads on the screw handle (Super- first, then heavier whites, sweet whites,
sink or bucket to catch drips, and gen- Jet) or the tightening knobs (Mini-Jet). light reds, heavy reds, and finally port.
tly pump the tank to force the water Never use any sort of tool to tighten the Rinse the machine with a gallon of
through the assembly. Don’t attempt to handles. This voids your warranty! fresh water between every filtration.
over-pump the tank. Wine should flow 5. Make sure all of the hoses are in Three pads is sufficient to filter at least
out at a rate of about a quart (one liter) place and tight. On the Super-Jet the one 6-gallon batch of wine, and more
every 30 seconds. intake hose attaches to the upper right often can do two or three.
7. If the plates leak, gently tighten the side of the machine as it faces away On the Super Jet, the pressure gauge
nuts until they stop. from you. The transfer hose goes from will indicate when the pads have be-
8. Continue to pump the tank as the the left-hand side of the motor into the come too clogged to filter any more.
flow slows down, until all of the water lower left corner of the plate assembly. When you are running water through
has gone through the pads. The outlet hose attaches to the top right the filter, the gauge will usually not
9. Empty the pressure tank and rack hand side of the plate assembly. On the show any pressure. When filtering, the
it full with your wine to be filtered. The Mini-Jet the intake hose attaches to the pressure will gradually rise from 1-2
pressure tank holds only a couple of right side of the pump, the output hose psi to 18-20 psi. When it reaches this
gallons, so you will need to refill it at goes from the left side of the pump to level, the pads need to be changed. On
least three times. It isn’t necessary to the bottom of the first plate, and the the Mini Jet, the flow will slow to the
sanitize the filter between fills, as one output hose comes out of the top left-
set of pads should be sufficient to filter hand side of the front plate.
an entire 6-gallon batch. Don’t over- 6. To catch small drips, place the ma-
pump the tank, but keep the flow rate chine in a sink or in a shallow pan large
steady and even. enough to extend under the pads, then
run six gallons (23 liters) of cold water
Using an electric system through the machine. This will wash
1. Sanitize all surfaces that will come any cardboard dust off the pads and
in contact with the wine. Dip the filter remove the remaining traces of sulfite
plates in a sulfite solution (or even bet- and citric acid. Check the machine for
ter, use a trigger spray bottle to coat leaks as it runs (gently tighten to elimi-
them with your sulfite solution). Run nate sprays or strong discharges of wa-
sulfite through the hoses and pump mo- ter) and empty the drip pan.
tor, and rinse everything. Return the
plates to the machine, making sure the Filtering your wine
semicircular tabs are on top and aligned 1. Dip the intake tube into the wine
with each other. to be filtered. If there is any sediment
2. Soak your pads in a solution of one in the container you should attach a si-
quart (one liter) of cold water with an phon rod (with a siphon tip) to the end
eighth of a teaspoon (0 .75 gram) of of the intake hose. This will prevent
metabisulfite and one teaspoon (3.5 g) sediment from getting into the pads and
of citric acid dissolved into it. If you clogging them prematurely.
don’t have any citric acid you can sub- 2. The filter works best if all contain-
stitute two teaspoons of lemon juice. ers are on the same level, or if the wine
Soak each pad in this solution, allow- being filtered is slightly higher than
ing it to saturate. When they no longer the receiving carboy. This reduces the
float, they are fully saturated. Do not amount of work that the pump motor
point where it becomes faster to change liter). If you are getting significantly entire batch in one go.
to a set of clean pads than it is to watch more leakage than this there may be • Don’t try to fill bottles directly from
the slow trickle from out of the ma- something wrong. It may be that the the filter. To do that you either have to
chine. plate assembly is not properly aligned turn it on and off (see above) or you
or is not assembled correctly. The pads have to pinch off the flow from the out-
Troubleshooting might be too fine, or simply plugged. put hose. This will result in huge back-
Wine does not move when pump Flow stops after a few gallons: pressure on the pad assembly and can
turned on: Positive displacement The wine is probably too cloudy to cause wine to spray everywhere.
pump filters, like the ones described be filtered, or you’ve chosen the wrong • If you filter a wine and see later that
above, are capable of self-priming grade of pads. Stop filtering and assess it bas thrown a sediment, this is usually
when new. But as they get older, the the wine. It may need fining, or you a fault of the fining and racking pro-
valves that move the mechanism weak- might have to use a coarser filter pad. cess rather than filtering. Most protein-
ens and can’t start the filtering action Pressure gauge never moves: based fining agents (gelatin, isinglass)
on its own. This is normal wear and The reading on the gauge will move will sail through a filter pad, and while
tear. To start the pump, prime it by fill- during filtering. If it doesn’t display they may not be visible in solution im-
ing the intake hose with water. Con- any activity it may be blocked by a bit mediately, after a week they’ll settle
nect it to the machine, dip the end into of debris. Ask your retailer for advice out as a milky haze in the carboy. Re-
the wine, and turn on the pump. If it on clearing it or on obtaining a replace- member, you can only filter wine that is
doesn’t begin to go immediately, there ment gauge. almost completely clear already.
may be something blocking the pump. • Carefully dispose of your pads as
Call your retailer. A few filtering tips soon as possible, sealing them tightly
Excessive leaking: Filter systems • Don’t turn the filter on and off while in plastic. They are a smorgasbord for
will typically leak about 5% of the filtering wine. This disturbs the struc- fruit flies, who bring along Acetobacter
wine being filtered. For a six-gallon ture of the pads and diminishes effi- (vinegar-producing bacteria).
batch this amounts to about 4 cups (1 ciency. Try to make sure you filter an