Using Lysozyme

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Using Lysozyme

Summary

Lysozyme is used primarily to prevent malolactic fermentations in aromatic white wines and to prevent the the geranium effect in wines with residual sugar and sorbate.

  1. Add 0.1 gram per liter to your white juice just after you have added your SO2 and given it time to bind.  The earlier you add Lysozyme the better. You can add Lysozyme at this stage even when you plan to introduce ML bacteria later.
  2. Add a further 0.2 grams per liter at the end of the fermentation if you want to prevent a malolactic fermentation.  Use more Lysozyme if you have a high pH or if you had a difficult fermentation.

In theory, Lysozyme can be used at higher doses (0.5 g/L) to stop a MLF fermentation part way though its course.

Prepare Lysozyme carefully according to the instructions below.

Make sure to fine your Lysozyme-treated wine for proteins before bottling.

Preparing Lysozyme

Lysozyme comes as a fine, rather fluffy, white powder, which must be dissolved carefully in water before use. It is a naturally occurring enzyme (protein) isolated from egg whites which degrades the cell wall of lactic acid bacteria (LAB) and thereby kills them. It has no impact on acetic acid bacteria or yeast.

  1. Measure out the amount you need for your wine (at least 0.2 grams per liter after fermentation).
  2. Put about 10 times as  water by weight in a container with a broad surface—the broader the better. The water can be room-temperature or lukewarm.
  3. Sprinkle some of the Lysozyme on top of the water. Let it dissolve of its own accord, which will take a few minutes.
  4. Sprinkle more Lysozyme and wait again. Continue until all Lysozyme is dissolved.
  5. Add to wine and stir very gently.

DO NOT try to stir your Lysozyme into the water. It will just glom together and take much longer to dissolve. Also do not vigorously stir or agitate your solution. Lysozyme is fragile.

Keeping Lysozyme: Store in a dry location. It will keep for a year at least with little loss in efficacy.

Why use Lysozyme

Commercially, Lysozyme is used in several situations:

  • To delay the onset of a MLF. White wines often do do not take well to a MLF occurring along with the yeast fermentation—stuck fermentations, excess acetic acid, and the like. Using Lysozyme at the juice stage delays the MLF until you introduce a specific ML bacteria after yeast fermentation is complete—when you get to choose the bacteria!
  • To kill lactic acid bacteria (LAB) and prevent a malolactic fermentation (MLF), especially in white wines where one wants to preserve the fruity character that is enhanced by the presence of malic acid.
  • To aid microbial stabilization after a MLF. For home winemakers, back-sweetened wines with sorbate are susceptible to a geranium taint because of the action of LAB bacteria on the sorbate.  Lysozyme can help prevent this.

Lysozyme’s effectiveness depends on the number of LAB cells present. You need more Lysozyme if you are killing more cells. Lysozyme acts within hours to kill LAB, but its killing effects do not last. Some LAB cell will remain or be introduced from elsewhere and populations can reestablish themselves.

Warning: Because Lysozyme is a protein it adds to the protein load in your white wines. This makes fining for protein before you bottle even more important that usual. Because Lysozyme helps a wine to clear, it is easy to forget this. Your Lysozyme-treated wine make look “star bright” in the carboy, but the proteins are still there and they will eventually form longer chains and precipitate in the bottle.

Alternatives to Lysozyme

There really are no alternatives to using Lysozyme as a way to actually kill LAB. However, certain environmental conditions limit the growth of the LAB population. These are:

        • Temperatures below 15ºC. (It is always a good idea to store your white wines at this temperature or lower.)
        • pH 3.1 or lower
        • Free SO2 above 35 ppm—which is easier to maintain at a lower pH

Using Lysozyme is advantageous in that it reduces the amount of SO2 you need to use to protect your wine.

The difficulty of ensuring these conditions is why using Lysozyme makes so much sense for the modern winemaker. So far as we know, there is no downside to using Lysozyme in white wines.

 

Further reading

Tim Patterson, “It’s Lysozyme Time,” Winemaker, June 2002.  Available at: http://winemakermag.com/407-it-s-lysozyme-time

Christophe Gerland, “Use of Lysozyme in Enology: Applications and Limits.” A paper by a French expert on the subject. Download the file.

Also see product details on the Scott Labs website: http://www.scottlaboratories.com/products/fermentation/microbialcontrol.asp

 Originally prepared by Rod Church, September 3, 2005. Most recently revised September 1, 2010.

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