Enology Notes

Enology Notes #22 June 29, 2001

To: Virginia Vintners

From: Bruce Zoecklein

Subject: Establishing a HACCP-like Plan

Establishment of a HACCP-like Plan.  Now is the time to establish a HACCP-like plan for the 2001 season. Each producer  should determine when, why and how wines should be evaluated by chemical, microbiological and sensory analysis. The establishment of a HACCP plan (hazard analysis and critical control points) allows for that determination. The creation of a HACCP plan involves making a flow chart of each and every step from vineyard to wine release. With this chart vintners can determine where the critical quality control points are located. Once the critical control points are identified, you need to decide how important these hazards are to quality and how controlled they should be.  For example,  could oxygen have been introduced at a particular step? Was it measured? Should it be?  Another example involves sulfur dioxide with the S02 specifications being much less critical in juice than at bottling. What are  the specifications for the two situations? What are the expected maximum and minium concentrations? How tight are the allowable ranges? How accurate must your analysis procedure be?  For each analysis conducted, it is necessary to know the expected maximum and minimum values,  acceptable values and the desired accuracy of the analysis.

A viticulture HACCP-like plan is as important as one for the winery. Such a plan should  also involve establishing a flow diagram. A viticuture HACCP-like plan should help to ask some important questions:  Do you have a written product handling specification agreement with the grower? Has the person responsible for spraying been certified? Can you verify that only approved chemicals  were used and applied correctly and at the proper time? This is a very important issue.  Last year a number of wine producers experienced the production of ‘reductive’ compounds such as H2S, mercaptans and dimethye disulfide.  Early season rains contributed to a high incidence of fungal degradation.  This incidence could have contributed to the production of reducing compounds.  Another factor could be late season sprays.  For example, a late spray of copper sulfate, considered rather begin by most growers, could significantly increase the yeast production of sulfur containing metabolities. Is grape quality compromised during transport?  Can your grapes be traced from the winery back to the particular block in the vineyard?  Can you provide records of all operations on your farm that affect grape quality?

HACCP Summary

The following is a list of red wine production issue.  From such a list a HACCP-like plan can be formulated to help monitor the critical control points.

Red Wines:

A matter of style:  Style is influenced by phenol maturity, extraction, and management.  The phenols of importance in reds: anthocyanins, flavonols, procyanidins, and polymers of these compounds and others such as polysaccharides and peptides.

Fruit ripeness

Different for different parts of the grape: seeds, skins, pulp, and stems.
Even ripeness among berries and clusters (See Long, 1997 PWV July/Aug)
Under vs. over ripe fruit
Ripeness rate and crop load
Ripeness by blocks

Fruit quality

Maturity Standards: defining maturity, sampling standards
Defining crop load

Berry size

Factors influencing berry size

Factors influencing berry phenols

cultivar, maturity, crop load, vineyard management including effects on solar exposure and temperature.
Fruit rot

Crushing and destemming

Importance of gentle fruit handling
Phenol extraction from stems
Phenol extraction from seeds

Fermentable N

Factors influencing N


Factors influencing co-pigmentation

Prefermentation maceration

Cultivar/time/temperature/aerobic vs. non/enzymes/SO2
Produce more complex wines?  More stable color?
Most flavonoids not very water soluble - flavor compounds are
Risk of biol. degradation


Measuring fermentable N
Nitrogen addition
TA adjustment
SO2 addition
Tannin addition
Fermentation with Oak/in Oak

Fermenter configuration and size

Fermenter style

Closed static fermenter
Open plastic bins
Rotary fermenters
Ducellien type auto
Padoran style vertical fermenter with in-place irrigation


Natural vs. cultured, species and strain, inoc. vol.


Species and strain, inoc. vol., timing

Temperature of fermentation

Liquid vs Cap

Cap management systems

Manual pigeage
Pumping oven
Time of draining
Whole cluster pressing
Post fermentation maceration



Less contact

Source of lees
Relative volume
Contact time
Mix. frequency

Role of O2

Role of SO2