vinmetrica SC-50 MLF, SC-50 User Manual

Vinmetrica SC-50 MLF Analyzer™

User Manual

The Vinmetrica SC-50 MLF (malolactic fermentation) Analyzer* is a simple and robust device that
provides high accuracy in determination of malic acid concentration levels in wine, an essential
parameter to control in the effort to make high quality wines.

Note: Check the Vinmetrica FAQ page for the most current version of this manual
with up-to-date procedures and best practices for operating your SC-50.
http://www.vinmetrica.com/FAQ

Table of Contents:

Materials Provided in the Kit............................................................................................................... 2

Things you will need............................................................................................................................ 2

Why Test for Malic Acid?.................................................................................................................... 3

Theory of Operation............................................................................................................................. 3

Setup.................................................................................................................................................... 4

Setting up the MLF Analyzer for the first time........................................................................ 4

Procedures.......................................................................................................................................... 5

Measuring Malic Acid............................................................................................................ 5

Confirming Procedure………………… .................................................................................. 7

Concentration Determination…………………………………………………………...….….8
Data Interpretation..…………………………………………………………………………...9

Finishing Up……………………………………………………………………………………...….10

Representative Data ……………………………………………………………………..…….........10

Warranties, Liabilities & Hazards.....................................................................................................11

Appendix A – Troubleshooting and FAQs ……………………....................................................12

*

US Patent pending

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Materials provided in the kit:

Figure 1. The SC-50 MLF

Analyzer with vial insertion

assembly

1. Vinmetrica MLF analyzer unit

2. Malic Reagent set:

Boost juice™ (Part Number: SC-50-4)
***Keep in Refrigerator***
Malic Acid (1M) concentrate (Part Number: SC-50-5)
***Keep in Freezer***
Malic Acid Standard Solution (0.40 g/L) (PN: SC-50-11)
***Keep in Freezer***
Malic Acid Standard Solution (0.10 g/L) (PN: SC-50-12)
***Keep in Freezer***

3. Biopressure Agent (PN: SC-50-3-10 or -20)

***Keep in Freezer***

4. Reaction Vials (5)

5. 1 ‘check’ vial

6. 10 ml serological pipette

7. 15 ml conical tube

8. Plastic bulb pipette (2)

9. 100 mL polypropylene beaker

10. Plastic Scoop

Things you will need:

1. Vinmetrica SC-100A or SC-300.

2. One 9 volt battery.

3. Distilled water, which usually can be found at your local grocery store. It’s handy to have a wash

bottle for rinsing. Rinse bottle available from Vinmetrica (Part number SC-100-17)

4. Microwave oven, hot plate or stovetop (for boiling wine samples)

5. (Optional) Additional Biopressure agent for running more than 5 samples, as provided in the kit.

Comes in sets of 10 (SC-50-3-10) or 20 (SC-50-3-20).

6. (Optional) BNC to RCA adapter - See under “Setup”, Step 4, for more information.

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Why Test for Malic Acid?

In winemaking, malolactic fermentation (MLF) converts malic acid to lactic acid, with CO
being the byproduct of the reaction. MLF, which is typically carried out in most red wines and in some

white varietals, plays an important role in the finished wine’s feel and taste. MLF reduces titratable

acidity, increases pH, and produces flavors often characterized as “soft” or “buttery”.

Sulfite, as free SO2, inhibits the bacteria that carry out MLF. Therefore free SO2 levels must be
kept low during MLF, carrying risks that the wine is left unprotected against oxidation and microbial
contamination. As soon as MLF is done, then, SO2 should be raised to appropriate levels for protection
of the wine. Thus it is important to know when MLF is done, and the best way to do this is to measure
malic acid levels in the wine.

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Theory of operation:

The SC-50 MLF Analyzer, with the SC-300 or -100A, can be used to determine malic acid
concentration in wine. It relies on the biochemical MLF reaction caused by enzymes found in certain
bacteria, including lactobacilli and oenococcus strains, and in the Biopressure agent component of the
kit. These bacteria live on a variety of nutrients, but their production of CO2 results almost entirely
from the enzymatic transformation of malic acid to lactic acid:

Malic Acid Lactic Acid
HOOC–CH2–CH(OH)–COOH  CH3–CH(OH)–COOH + CO2

The CO2 creates pressure, which is converted by the MLF Analyzer to a signal for the SC-300 (or
SC-100 or -100A). The CO2 pressure signal is directly proportional to the amount of malic acid in the
sample. The device is set so that when malic acid levels exceed 0.1 g/L1 (suggesting MLF is

incomplete), the user is alerted to this state by audible and visible indicators. The level of Malic acid
can be calculated from the digital readout by a calibrator of Malic acid provided with the kit. Detection
limit is below 0.04 g/L. The assay takes 30 minutes, or up to 60 minutes if the Confirmation Procedure
is performed (Page 8).

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On the original SC-100 model, the device will signal at a Malic Acid level of about 0.5 g/L. However, the sensitivity and

accuracy of malic acid values lower than this are comparable to those determined with the SC-100A and SC-300.

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Setup

Figure 2. Attach the SC-50’s

cable to the BNC or RCA

connector on the SC-300 (or

100)

Figure 3. Be sure the cable

plug is screwed into place on
the BNC connector or firmly

inserted into the RCA plug.

Figure 4. Recommended

arrangement of the

equipment

Figure 5. The adapter for

the SC-50.

Setting up the MLF Analyzer for the first time:

1. The MLF Analyzer runs on one 9 volt battery. To insert the battery, slide open the battery

housing on the bottom of the back of the unit by gently pushing the lid.

2. Low Battery Detection: If the battery is good, the POWER LED will stay illuminated when the

switch is pressed ON. When the battery level is too low, the LED on the POWER switch will
flash on briefly and then shut off. Replace the battery.

3. Before connecting the SC-50, turn on your SC-100A or 300 (on the SC-300, select SO2 mode,

press Enter) and wait for the initialization and green ‘Proceed’ light.

4. Now attach the MLF Analyzer to your SC-100A or 300 via the SO2 electrode connector

protruding from the top. Be sure to secure the electrode plug to the connector to ensure proper
function. Note: on earlier SC-100A or -300 models, there is just one BNC-style connector for
this purpose - see Figures 2 – 4. On newer models (June 2014) there is a separate phono- style
SO2 connector that will require an adapter for SC-50 models that have a BNC plug (Figure 5)–
contact us if you need one.

5. Prepare all Reaction Vials:

a. Remove Biopressure Agent from freezer and allow to come to room temperature.
b. Using the small plastic spoon provided, measure out two (2) level scoops (approx. 35-40

mg) of Biopressure Agent into each Reaction Vial.

a. Due to the consistency of the Biopressure Agent, we recommend rinsing and

completely drying the plastic spoon after filling approximately 5 vials.

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c. Cap all Reaction Vials.
d. Keep out all Reaction Vials needed for MLF assay.

a. For Quick Check Mode, you will need one (1) reaction vial per wine sample.
b. For Quantify Mode you will need at least two (2) reaction vials, one (1) for the

Malic Acid Standard and one (1) per wine sample. (See Quantify Mode, pg 8, for
further information).

e. Place all remaining reaction vials in freezer until use.
f. Thoroughly rinse plastic measuring spoon with DI water.

Procedures

Biopressure Assay method:

There are two modes for using your SC-50 to assess MLF status by Biopressure assay. Both modes use
steps 1 through 18 below.

 In the Quick-check Mode, you set the instrument such that if your sample has 0.1 g/L or more

of malic acid, you will see the STOP LED on the SC100/300 illuminate and the tone will sound,
alerting you that MLF is not complete. There is an optional confirmation step (see
Confirmation Procedure, page 8) that you can run after the test to verify the validity of a
result.

 In the Quantify Mode, you set the instrument to higher sensitivity and run the assay with one or

more malic acid standards provided in the kit. This allows you to determine the actual malic
acid concentration in your wine samples. (See Quantify Mode Procedure on page 8).

We recommend running the Quantify Mode until you are familiar with the workings of the instrument.

Note: the following procedure is designed to be run at room temperature, between 66 and 73°F
(19 - 23°C). Results may differ if temperatures are outside this range. See Appendix for more
information.

1. Take out all Reaction vials needed for assay from freezer. One Reaction vial per sample is

necessary. If you will run the assay in Quantify Mode you will need at least one additional
reaction vial (See Quantify Mode Procedure on page 8). Allow Reaction vials to come to
room temperature before initiating assay. Note that you can run multiple wine samples at one
time.

2. Using the 10 mL serological pipette, measure a 10 mL wine sample and dispense into the 100

mL plastic beaker or other suitable container. (Serological pipette can be rinsed with DI water
for re-use; remove cotton plug if necessary)

3. Place wine sample in microwave and boil for 90 seconds at medium power. Actual time

depends on your microwave oven’s power; the object is to get the wine sample to a gentle boil

for 60 seconds without having the wine splash out of beaker. If you are unsure about the power
of your microwave, we suggest you experiment with a couple of wine samples beforehand to
determine what the best settings are for your microwave oven. You may also bring wine to a
gentle boil on a stove top for 60 seconds.

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