vinmetrica sc-300 kit User manual

SC-300 manual 1 Version 3.0a
Vinmetrica SC-300 Kit™
User Manual
The Vinmetrica SC-300*is a simple and robust device that provides high accuracy in determination of
sulfite (SO2), pH and titratable acidity (TA) levels in wines, ciders, and other liquids. These are
essential parameters to control in the effort to make high quality wines.
Table of Contents:
Materials Provided in the Kit............................................................................................................... 2
Things you will need............................................................................................................................ 2
Why Test for SO2, pH and TA?............................................................................................................ 3
Theory of Operation............................................................................................................................. 4
Setup.................................................................................................................................................... 5
Setting up the SC-300 for the first time................................................................................... 5
Instrument Operation....................................................................................................................... 7
Procedures.......................................................................................................................................... 9
Measuring Free Sulfite (SO2) by Titration.............................................................................. 9
Measuring Total Sulfite (SO2) by Titration.............................................................................. 12
Calibration of pH .................................................................................................................... 12
Measuring pH........................................................................................................................... 13
Measuring Titratable Acidity (TA) by Titration....................................................................... 13
Finishing up............................................................................................................................. 16
Warranties, Liabilities & Hazards.................................................................................................... 17
Appendix A - Test Mode..................................................................................................................... 18
Appendix B - Sulfite & TAAdjustments........................................................................................... 20
Appendix C1 - Troubleshooting: pH and TAIssues........................................................................ 21
Appendix C2 - Troubleshooting: SO2Issues.................................................................................... 24
*US Patent pending

SC-300 manual 2 Version 3.0a
Materials provided in the kit:
1. Vinmetrica SC-300 SO2/pH controller unit (Part number SC-300-1)
2. SO2Electrode (Part number SC-100-3), blue polycarbonate housing
3. pH Electrode (Part number SC-200-7), red or blue polycarbonate housing
4. SO2Reagent set (Part number SC-100-2):
SO2Titrant Solution (0.0156N)
SO2 Acid Solution
SO2 Reactant Solution
5. pH/TA Reagent Set (Part number SC-200-8):
pH 4.01 Reference Solution
pH 7.00 Reference Solution
TATitrant (0.13 N NaOH)
6. Two 5 mL syringes
7. Two 3 mL polyethylene transfer pipettes
8. One 25 mL serological pipette
9. One 5mL serological pipette
10. 100 mL polypropylene beaker
Things you will need:
1. Two standardAA batteries (alkaline type).
2. Distilled water (aka purified water by deionization), which can be found at most grocery stores.
3. (Optional but highly recommended) It’s handy to have a wash bottle for rinsing. Rinse bottle
available from Vinmetrica (Part number SC-100-17, or included in the Deluxe Lab Accessory Kit).
4. (Optional) Deluxe Lab Accessory Kit which includes: magnetic stirrer, burette (10mL or 25mL),
lab support stand, electrode holder, and wash bottle. Available from Vinmetrica (Part Number SC-
300-9).
5. (Optional) Sodium Hydroxide solution, 1N concentration (if you want to do total SO2). Available
from Vinmetrica (Part number SC-100-7)
Figure 1. The SC-300 instrument with the SO2
and pH/TA electrodes.

SC-300 manual 3 Version 3.0a
Why Test for SO2, pH and TA?
Testing for sulfite (SO2) is crucially important for making sure your wine does not spoil by
oxidation or from microbial growth. By monitoring your SO2levels, you can make adjustments when
needed, especially before starting primary fermentation, after malolactic fermentation has completed,
after racking or when ready to bottle. To correctly adjust sulfite, you need values for your current "Free
SO2" level and your wine's pH, both of which can be measured with the Vinmetrica SC-300 analyzer.
The key parameter in protecting your wine is molecular SO2which for most wines should be at
0.8 ppm (mg/L) following secondary fermentation. This in turn depends on the free SO2(it can also be
referred to as unbound SO2) and the pH. Overall, you can reach your target molecular SO2by
measuring and adjusting your free SO2levels and considering your wine's particular pH. See Table 1.
Table 1. Free SO2concentrations necessary to attain 0.8 mg/L molecular SO2at a designated pH.
Free SO2(ppm)
13
16
21
26
32
40
50
63
79
99
125
pH
3.0
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
4.0
We recommend using a sulfite calculator for determining how much sulfite to add to your wines
after taking a sulfite measurement with the SC-300 Analyzer Kit. Winemaker Magazine's Sulfite
Calculator at http://winemakermag.com/guide/sulfite can walk you through the process. See Appendix
B for more information on how to adjust your wine for sulfite.
Monitoring your wine's pH is also important for the first few months of the wine making
process. Proper pH and Titratable Acidity (TA) levels influence mouth feel and provide wine stability.
During malolactic fermentation, the pH can increase somewhat and should be monitored. Typically,
wine pH and TA are inversely related; when pH goes up, TA goes down and vice versa. Adjustments
may be made to your wine to prevent wine instability. See Appendix B for more information on
adjustments.

SC-300 manual 4 Version 3.0a
Theory of operation:
Sulfite (SO2): The SC-300, with the SO2 electrode and reagents provided, can be used to determine
sulfite (or SO2)levels in wine, musts, and other samples. It relies on the Ripper titration based on the
quantitative reaction of the SO2with iodine (generated during the titration) which oxidizes the SO2in
the sample under acid conditions.
IO3-+ 5I-+ 6H+3I2+ 3H2O generation of iodine from iodate
SO2+ I2+ H2O 2I-+ SO3 + 2H+reaction of SO2and iodine
When all the SO2is titrated at the endpoint, excess iodine appears in solution. This is detected as
current with the SO2electrode and signaled by audible and visual indicators. The endpoint is much
more sensitive than the starch color change commonly employed for Ripper titration, and it is sharp
and clear, even when titrating red wines and musts. From the known concentration of the titrant and its
volume required to reach the endpoint, the free SO2is simply calculated.
pH and TA: The SC-300 kit also provides a pH electrode and reagents for calibration and
determination of pH and titratable acidity (TA) values in wines and other samples. The pH value is
simply determined by placing the calibrated electrode into a sample and reading the value. TA is
determined by titrating a 5 mL sample of wine to an endpoint pH of 8.2* (or 7.0 if preferred, see below)
with the TA titrant (0.13N NaOH) from the syringe in the kit. From the known concentration of the TA
titrant and its volume required to reach the endpoint, the TA is simply calculated (results are in units of
g/L tartaric acid).
Potential measurements: In firmware versions 3.1.1 and higher of the firmware, the SC-300 can
display the voltage reading on an electrode attached to the pH connector. This can be used with certain
electrodes, for example, galvanic oxygen probes, potassium, or sodium electrodes, or to view the raw
voltage reading of a pH electrode.
*In some countries, pH 7.0 is used as the endpoint; see Instrument Operation, Step 5 (page 7).

SC-300 manual 5 Version 3.0a
Setup:
Setting up the SC-300 for the first time:
1. The SC-300 (Figure 1) runs on two standardAA batteries (alkaline cells recommended). To
insert the batteries, open the battery housing on the bottom of the back of the unit by removing
the two screws and gently prying off the lid. Install the batteries, then close the housing. If
desired, you can prop the unit up using its folding stand.
2. Low Battery Detection: When the battery level is getting low, the instrument shows a low
battery icon on the upper left side of the display but continues to operate without impairment of
any function. Replace the batteries as soon as practicable. When the battery level drops too far,
the instrument does not operate. It rapidly flashes the low battery icon for 3.0 seconds, beeps
and shuts itself off.
3. Auto Shut-off: The SC-300 shuts off after 30 minutes. If this happens unexpectedly, just press
the POWER button to resume from where you were.
4. Electrodes: When directed to do so, attach the desired electrode (SO2or pH, Figures 2 & 3) via
the proper connector protruding from the top (on earlier model SC-300s, there is just a single
connector for both electrodes). Be sure to secure the electrode plug to the BNC connector to
ensure proper function.
5. SO2electrode: Remove any protective cover from the electrode tip (most electrodes are
shipped without one). This cover need not be used routinely. Put the electrode on its side, or
hang it from an electrode stand if you have one. The SO2 electrode is sturdy with its plastic
housing, but do take care not to let things touch or strike the platinum wires; they are somewhat
fragile and will break if bent and straightened repeatedly. Attach the SO2 electrode to the proper
Figure 2. Attach the SO2 electrode
to the connector on the SC-300.
Figure 3. Be sure the pH
electrode attachment is screwed
into place on the BNC connector.

SC-300 manual 6 Version 3.0a
connector. In some cases this is a BNC-style plug as in figure 2; on older units this may be a
phono style plug (not pictured). Electrode care: When done, always rinse with DI water and let
air dry. There is no need to store the SO2electrode in any kind of solution.
5. pH electrode: Attach the pH electrode via the BNC connector on the top of the SC-300
(Figures 3). The pH electrode is fragile and should always be handled carefully. Remove the
liquid storage bottle from the electrode by unscrewing the cap first, then gently removing the
bottle and pulling off the cap. Rinse the electrode with distilled water before each use.
Electrode care: Do not touch the glass bulb, nor attempt to wipe it with anything. When
necessary, you may gently blot excess liquid away from the electrode surface, but avoid directly
touching it. When finished using the electrode, rinse the electrode with DI water and gently blot
or shake off excess water. Push the electrode through the hole in the cap about an inch and
gently screw the bottle onto the cap so that the electrode is in contact with the solution in the
bottle. The pH electrode should always be kept in the liquid storage bottle with its pH
Electrode Storage Solution (Part Number SC-200-10) when not in use.
Note: We recommended replacing the pH Electrode Storage Solution once a year or when the solution
becomes cloudy or moldy.

SC-300 manual 7 Version 3.0a
Instrument Operation:
1. Disconnect any electrodes. Turn on the instrument by pressing the POWER button briefly (Note:
depressing the POWER button longer than two seconds at start-up will cause the instrument to
enter Test Mode; see Appendix A). The instrument will go through a power-up sequence. After
a few seconds the instrument will start in whatever mode was last selected. The mode is
indicated by the yellow LED panel on the left. Select the desired mode by pressing the MODE
button.
2. SO2mode: This is for titration in determining ppm of SO2 (see below under ‘Procedures’)
where the SO2 electrode must be used. [Warning: On older style, single connector units (pre-
2014), the pH electrode can be damaged by connecting it to the instrument in SO2 mode. As a
safety precaution, on these older units after selecting SO2 mode you must press the ENTER
button after selecting SO2 mode to confirm that the SO2 electrode is attached before the mode
will be enabled. However, scrolling through the MODE selections (such that you pass by the
SO2 selection) with a pH electrode attached is safe, as long as you do not press ENTER to
confirm the SO2 mode.] You should see the display show a value less than 50 (usually 0.0) and
the green "PROCEED" LED should be on.
3. pH mode: In this mode, the meter measures the pH. The pH electrode must be attached. If the
instrument has not yet been calibrated, the message “do Cal” scrolls across the screen, and you
will need to do a calibration (see “Calibration of pH”below). We recommend re-calibrating the
instrument for pH once each day of use, or whenever the Reference solutions do not give the
expected pH in pH mode. Warning: Be careful on earlier (pre-2014/single connector) versions
not to press ENTER when the pH electrode is attached while the instrument is in SO2mode, as
this can potentially damage the pH electrode. If this does happen, and the pH electrode does not
respond correctly, place it into the pH 4 Reference solution for an hour and it should return to
normal function. With recent versions there are two separate connectors; the pH electrode
should be attached to the silver BNC connector.
4. Potential mode (Firmware version 3.1.1 and higher) (pH LED flashing): In this mode the
instrument displays the potential (in volts, version 3.1.1, or millivolts, v 3.1.2) coming from an
electrode attached to the pH connector. This can be used with certain electrodes, for example,
the Vinmetrica Dissolved Oxygen probe, ORP, potassium, or sodium electrodes, or to view the
raw voltage reading of a pH electrode. In this mode, when the red STOP LED is illuminated,
the values on the screen are negative; otherwise the values are positive.
5. TA mode: This is for titration in determining titratable acidity (TA). As in the pH mode, the pH
is displayed and the pH electrode must be attached. The green (“PROCEED”) LED is lit if the
pH is below the TA endpoint (normally 8.2, but can be set to 7.0, see Appendix A, Test Mode,

SC-300 manual 8 Version 3.0a
section 16), while the red "STOP" LED is lit if the pH is above the endpoint (see below under
Measuring TA by Titration).
6. CAL mode: This is for calibrating the pH electrode, which must be attached. The display
initially shows “CAl”for a few seconds as it prepares to read pH and lets readings settle.
Thereafter, the display shows the measured pH level with two decimal places.
7. Calibration works with one of the following reference calibration sets:
pH 4.01 and 7.00 or “4/7”
pH 7.00 and 10.00 or “7/10”
pH 3.00 and 7.00 or “3/7”
Vinmetrica recommends use of the pH 4/7 Reference Solution set provided with the kit.
8. The pH electrode: The pH electrode should always be kept in the liquid storage bottle with
plenty of storage solution (pH electrode storage solution; Part Number SC-200-10) when not in
use. If there is an odor, if the liquid is cloudy or moldy, or you suspect the electrode storage
solution has been compromised please replace it immediately. Over time, improper storage of
the electrode can damage its functionality.
9. (Optional) The magnetic stirrer (Included in the SC-300 Pro Kit, or bought separately) has two
modes. Pressing the "light bulb" button on the magnetic stirrer activates a light underneath the
sample and the stirrer. The power button activates just the stirrer. After pressing either button,
the stirrer remains active for 60 seconds, a feature to conserve its batteries. If during the
titration it turns off, simply press the button again for it to continue. We recommend using the
light mode because it helps us indicate when the stirrer stops. Plus when doing TA titrations
watching the wine turn from deep red to dark green is cool!
Note: When using the magnetic stirrer, be sure that the electrode does not touch the spinning
stir bar as there is a slight chance that it can damage the glass bulb of the pH electrode or the
platinum wires of the SO2electrode. If you are using the Vinmetrica Electrode Holder, adjust
the electrode’s height so that its probe end is above the level of the stir bar.

SC-300 manual 9 Version 3.0a
Procedures
Measuring Free SO2by Titration:
1. Turn on the instrument and select SO2mode using the MODE button. On older instruments,
you need to press ENTER to confirm selection of SO2 mode (Figure 4). The display should
show a value less than 20, usually 0.0. Now attach the SO2 electrode. [You do not need to repeat
this start-up sequence each time you do a test]
2. Fill the syringe by drawing up the SO2Titrant Solution (the bottle with the blue label)
(Figure 5). Expel bubbles and set the plunger on the syringe to a readable point, preferably the
5.0 mL point. Make sure the outside of the syringe is dry, to minimize any inaccuracies. [Note:
the 5.0 mL setting allows determination of up to 100 ppm SO2in a standard 25 mL wine
sample.] Be sure to record your starting syringe volume.
If using a burette, use the syringe to dispense the SO2Titrant Solution into the top of the burette.
Make sure the burette stopcock is in the closed position (i.e., the handle is horizontal). When
filling the burette, make sure the SO2titrant has completely filled the bottom of the burette
including the tip. Sometimes bubbles can be trapped in the tip of the burette but can usually be
dislodged by opening and closing the stopcock while the burette is above a waste container. If
you spill any titrant on the outside of the burette, be sure to clean it up with a paper towel or dry
rag. If the spilled titrant is not cleaned from the outside of the burette, you may introduce these
spilled titrant droplets into the wine sample leading to an inaccurate reading. Be sure to record
Figure 4. Once in SO2
Mode the instrument
may request that you
press ENTER to activate
SO2 Mode.
Figure 5. Withdraw the
titrant from its bottle
using a clean 5 mL
syringe. If you are using
the glass burette, use the
syringe to fill it.
Figure 7. The transfer
pipette. One full squeeze
of the transfer pipette in
either the Acid solution
or Reactant should be
approximately 2 mL.
Figure 6. Dispense 25
mL of your wine into the
titration beaker using the
25 mL sampling pipette.
Make sure this is clean
before putting the pipette
into your wine container!

SC-300 manual 10 Version 3.0a
your starting burette volume. Refer to 'Burette Reading' section under the Setup section for
how to measure accurately.
3. Place 25 mL of wine or must in the titration vessel. We recommend using the 25 mL sampling
pipette provided in the kit: draw the sample up to the 0 mL mark, and then dispense the sample
into your titration vessel by letting the tip of the pipette touch the side of the vessel while the
sample drains (Figure 6). NEVER pipette any reagents by mouth! Make sure the pipette
you are using is completely clean before submerging into your wine sample. (We
recommend using a 50% ethanol solution, Do Not use a sulfite solution to sanitize before
sampling)
4. Using the transfer pipettes (Figure 7), add about 2 mL SO2 Acid Reagent and 2 mL SO2
Reactant Solution to the titration beaker (be sure to label the transfer pipettes to avoid cross
contamination, we recommend “A” for Acid and “R” Reactant). It is not necessary to be
extremely accurate in this step; with these pipettes, 2 mL is roughly the amount that fills the
pipette up to the 2 mL mark after a single thorough squeeze of the bulb. To preserve the shelf
life of these reagents take care not to cross contaminate the transfer pipettes. If they do get
contaminated rinse them out with distilled water and let air dry. Caution: the SO2 Acid
Solution reagent is corrosive and can cause damage to clothing, skin and eyes. The
reagents should not be ingested. ALWAYS use safety glasses! We recommend the use of
laboratory latex or nitrile gloves during this procedure. If any solutions contact skin or
eyes, flush with plenty of water.
5. (Optional) If you are using the magnetic stirrer, place the stir bar in the beaker, place the beaker
on top of the magnetic stirrer and turn the magnetic stirrer on. The magnetic stirrer operates at a
suitable preset speed. Make sure your electrode is not struck by the spinning stir bar. To prevent
this, we recommend using the Electrode Holder to stabilize your electrode.
6. Rinse the electrode briefly with distilled water. Insert the electrode into the titration beaker so
that the tip is completely submerged to just above the circulation gaps (cutouts at the tip of the
electrode). If you are stirring manually, begin now; use a constant moderate swirling motion. If
the electrode is not held in a stand, hold it against the side of the vessel with one finger and
grasp the vessel with the remaining fingers so that the two move together (Figure 8).
7. (Optional) If you are using the magnetic stirrer, ensure the tip of the electrode is completely
submerged to just above the circulation gaps but above the level of the stir bar (approximately
half an inch from the bottom of the titration beaker). If you are using the Electrode Holder
adjust it to a similar level. If needed, you can add up to 25mL of DI water to raise the liquid
level.