vinmetrica SC-300 User Manual

Vinmetrica SC-300 Pro Kit™

User Manual

Vinmetrica SC-300* Pro Kit 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. The Pro kit includes lab accessories for the SC-300 Analyzer.

Table of Contents:

Materials Provided in the Kit...............................................................................................................

Things you will need............................................................................................................................

Why Test for SO2, pH and TA?............................................................................................................

Theory of Operation.............................................................................................................................

Setup....................................................................................................................................................

Setting up the SC-300 for the first time...................................................................................

Assembling the Pro Kit Equipment.........................................................................................

Burette Maintenance................................................................................................................

Burette Reading .......................................................................................................................

Instrument Operation.......................................................................................................................

Procedures...........................................................................................................................................

Measuring Free Sulfite (SO2) by Titration..............................................................................

Measuring Total Sulfite (SO2) by Titration..............................................................................

Calibration of pH .....................................................................................................................

Measuring pH...........................................................................................................................

Measuring Titratable Acidity (TA) by Titration.......................................................................

Finishing up.............................................................................................................................

Warranties, Liabilities & Hazards....................................................................................................

Appendix A - Test Mode.....................................................................................................................

Appendix B - Sulfite & TA Adjustments...........................................................................................

Appendix C1 - Troubleshooting: pH and TA Issues.......................................................................

Appendix C2 - Troubleshooting: SO2 Issues...................................................................................

US Patent pending

SC-300 Pro Kit Manual 1 Version 2.2

Materials provided in the kit:

Figure 1. The SC-300 instrument

1. Vinmetrica SC-300 SO2/pH instrument

(Part number SC-300-1)

2. SO2 Electrode (Part number SC-100-3)

3. pH Electrode (Part number SC-200-7)

4. Two 5 mL syringes

5. Two 3 mL polyethylene transfer pipettes

6. One 25 mL serological sampling pipette

7. One 5mL serological sampling pipette

8. 100 mL polypropylene titration beaker

9. SO2 Reagent set (Part number SC-100-2):

SO2 Titrant solution (0.0156N) Acid reagent Reactant solution

10. pH/TA reagent set (Part number SC-200-8):

pH 4.01 Reference solution pH 7.00 Reference solution TA Titrant (0.133N NaOH)

11. Lab Support stand (Part number SC-300-3)

12. Electrode Holder (Part number SC-300-8)

13. Double Burette Clamp (Part number SC-300-6)

14. 10 mL or 25 mL Glass burette with Teflon Stopcock (with ~2 grams of Burette detergent)

(Part number SC-300-7)

15. Magnetic Stirrer (includes two AA batteries, stir bar and 25 mL cylindrical container)

(Part number SC-300-4)

16. Rinse Bottle (Part Number SC-100-17)

Things you will need:

1. Two standard AA batteries (alkaline type).

2. Distilled water, which usually can be found at your local grocery store (aka purified water by

deionization).

3. (Optional) 1N Sodium Hydroxide solution (if you want to do total SO2). Available from

Vinmetrica (Part number SC-100-7)

SC-300 Pro Kit Manual 2 Version 2.2

Why Test for SO2, pH and TA?

Free SO2 (ppm)

125

3.0

3.1

3.2

3.3

3.4

3.5

3.6

3.7

3.8

3.9

4.0

Testing for sulfite (SO2) is crucially important for making sure your wine does not spoil by oxidation or from microbial growth. By monitoring your SO2 levels, 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 SO2 which 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 SO2 by measuring and adjusting your free SO2 levels and considering your wine's particular pH. See Table 1.

Table 1. Free SO2 concentrations necessary to attain 0.8 mg/L molecular SO2 at a designated pH.

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 Pro 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 Pro Kit Manual 3 Version 2.2

Theory of Operation:

1. 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 SO2 with iodine (generated during the titration) which oxidizes the SO2 in the sample under acid conditions.

+ 5I- + 6H+  3I2 + 3H2O generation of iodine (I2) from iodate (IO

SO2 + I2 + H2O  2I- + SO3 + 2H

reaction of SO2 and iodine

)

When all the SO2 is titrated at the endpoint, excess iodine appears in solution. This is detected

as current with the SO2 electrode 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 SO2 is simply calculated.

2. 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 pH 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* with the TA titrant (0.133N 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).

3. Potential measurements: In firmware versions 3.1.1 and higher, 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, Vinmetrica’s Dissolved Oxygen System, potassium, or sodium electrodes, or to view the raw voltage reading of a pH electrode.

*In some countries, pH 7.0 is taken as the endpoint; see Instrument Operation, Step 6 (page 11).

SC-300 Pro Kit Manual 4 Version 2.2

Setup:

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.

Setting up the SC-300 for the first time:

1. The SC-300 (See Figure 1) runs on two standard AA 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 (SO2 or 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). Your electrodes and/or instrument may have different connectors than what is shown in the figures below. Be sure to secure the electrode plug to the BNC connector to insure proper function.

5. SO2 electrode: 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 the electrode holder if you have one. The SO

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.

SC-300 Pro Kit Manual 5 Version 2.2

Electrode care: When done, always rinse with DI water and let air dry. There is no need to store the SO2 electrode in any kind of solution.

6. pH electrode: 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 a little 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. 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, then gently screw the bottle onto the cap so that the electrode is in contact with the solution in the bottle. If you happen to spill your pH electrode storage solution, your pH 4.01 solution (SC-200 pH/TA Reagents) can be used as a temporary storage solution but you should order more pH electrode storage solution as soon as possible. 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: It is recommended to replace your pH electrode storage solution once a year or if the solution becomes cloudy or moldy.

Assembling the Pro Kit Equipment:

Remove the items from their packaging: the Lab Support Stand, the Electrode Holder, the

Double Burette Clamp, the Glass Burette, Rinse Bottle and the Magnetic Stirrer. Carefully pull out the glass burette from its cardboard cylindrical container and out of its container. Use caution not to exert too much force on the burette as it is fragile and can break.

Open the Magnetic Stirrer from its packaging, then insert the double AA batteries included. We

recommend you do not use the cylindrical container provided with the magnetic stirrer but use the 100mL titration beaker (Figure 4) included with the SC-300.

Assemble the Lab Support Stand by attaching the long metal rod and screwing it into the large metal base. We have found that adding a drop of super glue to the threads of the metal rod can prevent loosening of the assembly. Then place the magnetic stirrer below the lab support stand as shown below in Figure 4.

To attach the Electrode Holder, loosen the thumb screw on the Holder and slide it onto the Lab

Support Stand rod (Figure 5), then tighten the thumb screw to adjust it to an appropriate height (Figure 6). Make sure the thumb screw is on the left side of your set up.

Attach the Double Burette clamp to the Lab Support Stand using its thumb screw to adjust for

height, as shown in Figure 7 below. Place the Double Burette Clamp a few inches above the electrode holder.

SC-300 Pro Kit Manual 6 Version 2.2

Figure 4. The Magnetic

stirrer and beaker with the pH electrode inserted into

the Electrode Holder

to the wine sample.

Figure 5. The Electrode

Holder slides onto the Lab

Support Stand.

Figure 7. The Double

Burette Clamp slides

easily onto the Lab

Support Stand.

Figure 6. The thumb

screw makes adjusting

The Electrode Holder's

height easy.

Carefully open the Double Burette Clamp's spring arms with your thumb and forefinger and

place the burette in between the four indentations in the double burette clamp's spring arm's plastic knobs (Figure 8 below). Slowly release the clamp spring to secure the burette between these four spring arm plastic knobs. You can adjust the burette at any time by raising and lowering it within the spring arm clamps of the Double Burette Clamp. When making these adjustments, hold onto the burette and do not apply too much force to it as the burette is delicate. Use the end of the Electrode Holder as a guide for the tip of the burette (Figure 9). DO NOT try and force the burette into the cutout at the end of the electrode holder. This may cause your burette to snap and break. Finally, insert the electrode that you wish to use into one of the open side slots. Once the black rubber neck of the electrode is sitting on top of the electrode holder, stabilize the electrode holder and then press the electrode down so the electrode is further stabilized into the slot. Remember to be gentle with the electrode.

You are now ready to titrate!

Note: The magnetic stir bar that is placed within the 100 mL titration beaker can potentially

damage the SO2 and pH electrodes. When adjusting the height of the electrodes, make sure that the stir bar in the beaker is below the bottom of the electrode. You do not want the spinning magnetic stir bar to strike the SO2 or pH electrode. When titrating for SO2 or TA, you can add a few milliliters of distilled water to raise the liquid level in the titration beaker by a half inch or so.

SC-300 Pro Kit Manual 7 Version 2.2

Figure 8. The burette sits

firmly between the notches of the four

spring arm knobs of the

Double Burette Clamp.

Figure 9. Use the end of

the Electrode Holder as a

guide for the glass burette

for accurate titrations.

Figure 10. The Pro Kit

Assembly is complete. Go

take some measurements!

Burette Maintenance

Keep the burette clean and wash with deionized (distilled) water when you are finished using the burette. This is especially important for TA titrations because the TA Titrant is caustic and can etch the burette. Every so often, you will want to clean your burette with a cleaning solution to maintain accuracy of the burette. The included ~2 grams of Burette Detergent is specially formulated to clean glassware. The dry detergent ships in an Eppendorf tube that has markings with approximate half gram increments. Upon first receiving the detergent, mix approximately half a gram (about an 1/8th of a teaspoon) with about 50 milliliters (mL) of distilled water into a small bottle. We recommend capping the bottle and shaking well for a minute or until the detergent is dissolved. Bubbles may form but the detergent will still be effective. The detergent solution should be made fresh every time you clean the burette, as it loses its potency quickly if stored as a liquid.

After you have run distilled water through your burette, close the stopcock, and fill with the Burette Detergent solution. You can open and close the stopcock over a waste bucket or sink to allow the solution to pass into the tip of the stopcock. We recommend letting this detergent solution sit in the burette for one hour. Dispense the detergent solution then rinse the burette with distilled water twice more. During this time we recommend opening and closing the stopcock to make sure the stopcock is turning easily. If it is not, remove the stopcock and clean it thoroughly. Once drained, allow to hang dry by hanging the burette upside down with the stopcock in the open position. Once the burette is dry, flip it back over and cover the top opening with a piece of tape. This will prevent dust from getting in that can cause aberrations when reading the burette. Remove the tape when you're ready to titrate.

SC-300 Pro Kit Manual 8 Version 2.2

Burette Reading

Figure 11. On a thick white

sheet of paper or a business card,

use a black marker to draw a

band approximately an inch and

a half thick. This card will assist

you in reading the burette

accurately.

Figure 12. The meniscus of the

water column. We recommend

measuring the titrant volume

from the bottom of the

meniscus. In the picture the

value is about 3.27 mL.

Figure 13. Reading the meniscus of the water column is easier and more precise if you use the paper with the

black band held up an inch behind the

burette and its black band 1/2 an inch

below the meniscus. In this picture the

value from Figure 11 is further

resolved to 3.26 mL.

ALWAYS use eye protection and preferably gloves (latex or nitrile) when using glassware and chemical reagents. To get the most accurate results when titrating, there are a few things to keep

in mind. We recommend reading from the bottom of the meniscus (Figure 12). First, use a thick sheet of white paper, note card or the back of a business card and draw a black band down the center of the paper about an inch and a half thick (Figure 11). When taking a measurement, hold the paper about an inch behind the burette and the black band about a half an inch below the meniscus (Figure 13). This provides a clear view of the bottom of the meniscus which helps make a precise, consistent measurement. Second, when filling the burette, make sure the titrant (in most cases this will be either the SO2 Titrant or the TA Titrant) has completely filled the bottom of the burette including within 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 hovering over a waste container. We also recommend washing a couple of milliliters of the titrant you are using through the burette to remove any excess water or contaminants that may remain from a previous titration. Finally, make sure there are not any large bubbles in the burette after filling. If there are, cover the top of the burette with some saran wrap (or parafilm if you have it) and make sure the stopcock is in the closed position. Then take the burette out of its clamp and hold the saran wrapped end tightly. Rotate and invert the burette to allow the bubbles to move out of the column of titrant. Once the bubbles have been displaced, you are ready to titrate.

Note: the gradations on your burette may be different than shown in the figures below. These photos are of the 10 mL burette; the 25 mL burette will have fewer gradations. Please take a look at your burette and determine the values for the gradations (lines).

SC-300 Pro Kit Manual 9 Version 2.2

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vinmetrica SC-300 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual