Basic Winemaking - A Handbook
Bruce W. Hagen • September 2017
Contents
Basics winemaking – A Handbook 1
The basics: 1
What is winemaking?. 1
Basic differences between reds, whites and rosé wines: 2
Sanitation 3
Recommended alkaline cleaning products for winery cleaning: 4
Common sanitizers: 5
Cleaning and sanitizing your barrels: 6
Other ways to prevent microbial spoilage: 7
Using SO2 to ensure good quality wine: 9
The value of SO2: 9
Forms of SO2 ― free, bound, and total: 10
What does SO2 do and why you need to and add more during the wine making process? 10
The chemistry of SO2: 10
Stages of winemaking and SO2: 13
Adding SO2 and Potassium Metabisulfite: 14
Measuring SO2: 14
Ways to add SO2: 14
Factors affecting how much SO2 is needed: 15
The winemaking process - Getting Started 16
Sourcing grapes: 16
Cellar sanitation: 16
Harvest: 17
Temperature control: 18
Testing and adjusting the juice or must: 18
Adjusting °Brix: 18
Calculating how much water to add: 19
Acidity: pH: 19
Adjusting acidity (in a nut shell): 20
Common wine acid problems table: 21
The low down on adjusting pH: 21
The most common wine acid problems: 22
Making corrections: 22
Natural pH changes during winemaking: 23
Something to keep in mind: 23
Other options: 23
Problematic grapes: 24
Acidity: TA: 24
The ‘nuts and bolts’ of Adjusting TA: 24
Stemming/crushing 25
To sulfite or not to sulfite? Two options for fermenting white grapes: 26
SO2 addition: Pre-fermentation: 26
Skin contact: white and red grapes when making rosés: 27
Pressing white grapes: 27
Settling (clarifying) the pressed juice (whites): 28
Fermentation tannins for white grapes: 29
Racking (siphoning) settled juice from solids: 29
Preemptive Fining: (white juice): 30
Protein instability in white wines: 30
Other fining agents that can be added before fermentation: 31
Red grapes: Cold soak or cold maceration 31
Fermentation tannins: red grapes: 31
Fermentation: getting started 32
White grapes: 32
Red grapes: 32
Rehydrating yeasts and adding nutrition: both red and white grapes: 33
Adding the yeast mixture (red and white): 33
Yeast nutrition: (red and white): 33
Managing nutrient levels: 34
Other yeast-based nutrients: 36
Fermentation tannins (red and white fermentations): 36
Managing white grape fermentation: 37
Managing red grape fermentation: 37
Stuck fermentations: 39
End of primary fermentation for whites and Rosés: 39
Second SO2 addition (post fermentation ― (whites and rosés) 40
Aging wines ‘sur-lie’: 40
End of primary fermentation for red wines: 41
Extended maceration: optional 41
Pressing reds: 41
Malolactic fermentation (MLF): 42
Post MLF SO2 addition: 45
SO2 additions during storage and aging: 45
Limiting the loss/use of SO2: 45
Aging and clarification: 46
Fining: 47
Fining agents: 47
Racking: 49
Topping: 50
Pre-bottling SO2 additions: 50
Filtering: 51
Bottling: 51
Helpful numbers: conversions 52
Basics winemaking – A Handbook
Bruce Hagen
Introduction: This document has undergone a major revision since I introduced it last year. For me, it is still a work in progress. My intent for writing this was 2-fold: first to help me to focus on the most important aspects of wine making, and to explore a wide varieties of resources for advice, explanations, recommendations, and solutions to complex problems, etc., and second: to help GENCO winemakers improve their winemaking skills. The two most important and difficult aspects of winemaking are managing SO2 levels and adjusting acid.
There are many ways to make wine, but no single best approach. There are no rules, only guidelines and some accepted practices that have been shown by research and experience to improve success rate. What I’ve done here is to present some of the basic (time-honored, as well as science-based) practices useful in making wines that meet current commercial standards. Wine can be made without using cultured yeast, SO2, or any of the currently available fermentation aids (enzymes, tannin products, fining agents, etc., or use of high tech equipment — if that’s what you want. But unless you really know what you’re doing, the results are likely to be disappointing, to say the least. There are reason for following accepted practices, at least loosely, and areas where you have greater flexibility to be creative or to just let ‘nature’ do its thing. All of our technological advancements stem from trial and error, innovation, scientific research, and the desire to make a better wine or ‘widget’, for that matter. Some people would have you think that natural-made wines are necessarily better because they are natural, but that just isn’t so. Well, at least, I’m not buying it.
The basics:
What is winemaking? Simply put, it is the art and science of making wine. To the French though, winemakers refer to themselves vignerons or winegrowers rather than winemakers. They emphasize the cultivation of grapes for winemaking, and don’t make a distinction between growing grapes and making wine—the two are inextricably linked. Many wineries in France still use time-honored methods, but take advantage of modern technology. In other wine growing regions, like California, there are viticulturalists and winemakers. Yes, many winemakers are very involved with the growing of grapes for their wines, others not so much. There are some winemakers who strive to make wines as naturally as possible—minimal intervention. No question, they may make very fine wines that are long-lived, balanced, and often with minerality and a sense of place— terroir. While other winemakers use the latest new technologies to make big, bold, complex, well-structured, silky and opulent wines, but often overly alcoholic wines, unless adjusted downward using reverse osmosis. The question is what style do you prefer? So, it’s really up to you how you want to frame your style.
Basic differences between reds, whites and rosé wines:
§ The pH range for white grapes for still wines is from about 3.0 to 3.5 and the range for reds is generally of 3.5 to about 3.8.
§ The juice of both red and white grapes, with a few exceptions, is basically colorless. However, the pigments in red grapes provide the red to blue/red color that characterize red wines.
§ Tannins, found in both red and white grapes, are readily transferred to the wine during skin contact (whites and rosés) and fermentation (red grapes).
§ In general, white grapes and red grapes used to make rosés are chilled, de-stemmed, crushed, and pressed before fermentation. They are typically pressed within an hour or two, occasionally more, of crushing to prevent tannin and/or pigment extraction. The result is a fresh, fruity, and crisp wine. Too much skin contact, however, can result in a harsh finish or too dark a color. Limited skin contact, though, can add varietal character. French style rosés are usually pressed within a few minutes of destemming and crushing and have just a blush of color.
§ Whites are best fermented near 60°F. The ideal range for fermenting whites is 55 to 64°F
§ Red grapes are typically de-stemmed, crushed, ‘cold-soaked’ (optional), and the wine pressed-off the skins and seeds after fermentation. Skin contact is lengthy, so color and tannins are more intense. Red grapes must remain in intact with the juice during all or part of the fermentation process to make red wine. Tannins are important for developing structure and protecting the wine during cellaring and in the bottle. Fermentation temperatures range between 70° and 85°F. Many red fermentation may reach 90°F or higher for a short period.
§ Grapes for Rosé wines should be harvested at a lower Brix than for red wines. For the best results, pick from about 21.5 to 22.5 for crisp, fresh, fruit-forward roses. They can also be made in the traditional method by draining off a portion of red juice immediately or shortly after destemming/crushing red grapes and then fermenting separately from the rest. The objective is to increase the skin-to-juice ratio, so that the resulting red wine will have more intense aromas, flavor, pigments, and tannins. The French call this traditional method: saignée (to bleed). Rosès can be a useful byproduct or done expressly for that style of wine.
§ The juice of white and red grapes used for rosés are prone to oxidation, and therefore fermented in closed containers, e.g., stainless steel tanks, carboys (glass or food-grade plastic) or oak barrels and kept under an air-lock.
§ Red must (crushed grapes) and finished wine, due to high levels of tannins from skin contact, are more resistant to oxidation than whites. Red grapes after destemming and crushing are generally fermented in open-top fermenters to allow the ‘cap’ of grapes that rises to the surface during fermentation to be punched down back into contact with the ‘wine’ below. The fermenting juice can also be pumped over the cap to keep the skins moist.
§ Long, slow fermentation are thought to produce the best red wines. Commercial fermentation often take from 5 to 7 days to complete.
§ White grapes are typically fermented at lower (cool) temperatures to preserve varietal fruit aromas. Whites fermented at lower temperatures may take up to 2 weeks to finish.
§ Reds typically undergo a secondary (malolactic) fermentation (MLF) that reduces the wines acidity. Chardonnay wine, however, is often allowed to undergo MLF or inoculated with a ML culture.
Sanitation
If you’re like most home winemakers, you probably don’t clean and sanitize your equipment the way you should, or as often as you should throughout the winemaking process. That can lead to problems with your wine. Careful attention to cleanliness and detail will minimize potential problems.
Commercial wineries take cleaning and sanitation very seriously. They have strict protocols for doing both with all their winemaking equipment at the end of each cycle and the start of a new one. A lapse in sanitation can have significant impact on the quality and marketability of the final product. And they are usually fastidious about retarding oxidation and/or microbial spoilage and preventing accidental introduction of wild yeasts and bacteria during crush, cold-soaking of grapes, fermentation, MLF, practices, or afterward during extended maceration, as well as during racking, topping up, pumping, filtering and bottling.
Cleaning involves the removal of both inorganic and organic substances from the surfaces of winery equipment. Sanitation, on the other hand, is the reduction of microbes that can cause wine defects. This is not the same as sterilization and disinfection.
Water quality can be an issue in winemaking. Most municipal water that has been properly treated to keep microorganism below harmful levels is fine to use for rinsing. Well-water may however contain high levels or bacteria that could affect your wine, unless it is properly treated. Water that has been softened, pH adjusted, UV treated and filtered is generally fine to use for rinsing. Soft water, though, may leave a residue and is not good to use for diluting must or mixing with yeast and other wine additives, like yeast nutrients, enzymes, tannins, bentonite, etc. It also has a higher sodium level that can make a wine taste salty. Bottled water that has been filtered and chlorine-free is much better to use for dilution and mixing with yeast.
Sanitation begins with keeping your cellar reasonably clean, free of debris and any working surfaces clean and regularly sanitized. Event floors should be vacuumed and moped with a disinfectant, especially at the start of crush. Wild yeast and bacteria are all around us. They are in the air, on flat work surfaces, and on all your winemaking equipment. It is not easy or even necessary to remove or kill every bacteria or wild yeast cell that might spoil wine. It is important, though, to keep their numbers low to minimize development and the production of metabolites that create off-aroma and flavors.
In general, anything that comes in contact with harvested grapes, must, and wine should be cleaned and sanitized, within reason, including your hands, which are a great source of microorganisms such as lactic acid bacteria. There isn’t much that can be done to eliminate wild yeast and bacteria on grapes, but winemakers can pick into lugs or buckets that have been cleaned of surface cleaned of debris, dirt and staining. From that point on, grapes should be transported in clean and sanitized containers. Stemmer crushers, presses and tanks, open-top fermenters, etc., should be thoroughly cleaned and sanitized. Collection buckets, funnels, car boys, stoppers, bungs, stir rods, tools used to punch downs, etc., need to be clean and relatively sterile. Literally everything that the grapes will come into contact with need to be cleaned and sanitized.
Simply rinsing winery equipment such as siphon hoses and carboys after use does not remove all of the organic material, staining, and hard to see films or microorganism. You need to use an alkaline cleaning agent to remove organic material, staining and biofilms (a slimy material containing microbes embedded in polysaccharides) that are typically not visible. Mold often grows in the residual rinse water which contains a very dilute solution of wine-based nutrient that remains following a quick rinse. It may take 3 or 4 rinses to remove all of the wine-based residue in carboys, fermenters, tanks, gallon jugs, etc., that can be slow to dry. This may result in contamination of the next batch of wine. To prevent this, use a cleaning solution to remove films and staining, followed by a sanitizer. Star San, SaniClean or Iodine-based sanitizers such as Iodophor BMP or Io Star, as well as a 10% solution of PMBS or high proof ethanol are all good sanitizers. Some cleaning agents can sanitize as well, after adequate contact time, but need to be rinsed. Scrubbing and brushing may be needed to remove stubborn residue and deposits. Avoid abrasive scrubbing pads on plastic to prevent scratching. Scratched and roughened surfaces are more difficult to clean and sanitize. Cleaned and sanitized containers like carboys and beer kegs should be allowed to drain upside down until there is no visible water. They can be stored with a paper cup inverted over the neck of the bottle, or a wadded paper towel placed in the bung hole. Other containers can be stored with the cover in place.