SO2

The Highs and Lows

Lower Sulfur ProgramWhy?● Less Manipulated Product

○ Low SO2 wine isn’t necessarily a less manipulated wine

○ Willing to substitute other products?● Marketing● Export● Color Management● Sensory

Lower Sulfur ProgramMain objective:● Mitigate SO2 and SO2 binding compounds● Utilize the SO2 that exists efficiently

How:● In a nutshell, keep microbes and oxidation at bay

Lower Sulfur ProgramHow con’t:● Keep pH low

http://www.bcawa.ca/winemaking/so2use.htm © Charles Plant 2001

Lower Sulfur ProgramHow con’t:● Yeast Selection and Timing

○ Low SO2 & SO2-binding compound production○ Yeasts can produce a few ppm-90ppm of SO2○ Higher fermentation temps - less stress on yeast

○ Timing: Inoculating early w/ yeast, waiting for a week after MLF to add stabilizer

In short - genetics, temperature and stress cause SO2 production by yeasts

SO2 & SO2-binding compound analysis after 2.5mo aging in barrel

SO2 addition on grapes no no no6g/hL______________________________________________________________________________________________________________________

After MLF (mg/L) no 2 52______________________________________________________________________________________________________________________

Post MLF yes no no no______________________________________________________________________________________________________________________

CL35 (mg/L) 68 70 73 85______________________________________________________________________________________________________________________

Total SO2 mg/L 14 23 4423

Lower Sulfur ProgramHow con’t:● Keep Oxygen Low

○ Gas bubbling/blanket/manage headspace○ Vessel choice○ Cooler Temps○ Lees ○ Ascorbic Acid

■ Ascorbic best used in conjunction with SO2Ascorbic converts dissolved O2 to H2O2. Sulfur competes for H2O2. Without sulfur, the H2O2 will assist the oxidation of ethanol to acetaldehyde. Square 1.

Lower Sulfur ProgramHow con’t:● Higher phenolics and tannins● Cleanliness

○ Includes filtration among other things● Use other products

Lower Sulfur ProgramHow con’t:● Use other products

○ Yeasts○ Fining agents

■ Used to lower microbial loads■ Downside: strips wine of phenolics

○ Lysozyme■ Enzyme destroys some bacterial cell walls■ Downside: potentially binds color

Lower Sulfur Program● Use other products

○ Chitosan■ Compound isolated from Aspergillus niger

cell walls; destroys cellular walls (works for brett)

■ Downside: can delay ML○ Dimethyldicarbonate (tradename Velcorin)

■ Broad spectrum - yeasts, bacteria & molds■ Downside: need training & dosage machine

Lower Sulfur ProgramHow con’t:● Use other products

○ Sorbate■ Potassium salt of sorbic acid that stops

yeast from reproducing■ Great for when sterile filter isn’t available■ Downside: geranium taint, not super soluble

○ Herbs?

So far, a product that replaces all of sulfur’s broad abilities has not been found, but using other products can

assist in lowering sulfur requirements to do so.

Higher Sulfur ProgramWhy?● Consistency● Agebility● Organoleptics● Health benefits

○ SO2 takes the rap for biogenic amines● Functionality

Higher Sulfur ProgramFunctionality con’t● Antioxidant

○ Impedes acetaldehyde production, directly reduces acetaldehyde and reverses browning

● Bactericide○ Minimize microbiological activity○ Yeast/Bacteria tolerances changing

● Preservative

Wine follyhttp://winefolly.wpengine.netdna-cdn.com/wp-content/uploads/2014/01/sulfites-in-wine.jpg

Higher Sulfur ProgramHow to Implement● Pre-fermentation

○ Yeast as an alternative?● Larger doses vs. smaller doses● Testing every vessel● Use the Molecular Form!

○ “Free” SO2 is misleading

http://www.bcawa.ca/winemaking/so2use.htm © Charles Plant 2001

Practical Winery and Vineyard JournalJanuary/February 2009https://www.practicalwinery.com/janfeb09/page2.htm

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Thank You&

Happy Winemaking!