Tonight's lecture Grapes that are used for winemaking Grafting and phylloxera Viticulture Annual growing cycle of grapevines Determining ripeness Wine 3 Pruning and trellising Introduction to Enology Sustainable viticulture Grapevine pests 1/21/2014 1 2 Points to Consider Quality comes from the Vineyard Wine grape varieties are one of the few Opinions on the proper way to grow grapes fruits that are chosen for flavor instead of vary as much as they do for wine making. ease of processing or appearance. There are many factors that influence the Wine grapes are one of the few fruit crops quality of grapes. that get picked when ripe. The quality of the wine depends on the quality of the grapes; the winemaker can preserve quality but it is difficult to improve. 3 4 Why grapes for wine? Why grapes for wine? Because it is the perfect fruit for This is why the term "wine" has become fermentation. synonymous with grape wine. High concentration of fermentable sugar. Grapes are to winemakers as barley is to High nitrogen content for fermentation. brewers. Natural association of yeasts and grapes. Grapes have conditions that inhibit spoilage (high acid & tannins) 5 6 Viticulture 1 Fruit Wines Which grapes to use for wine? Wine can be made from a number of fruits besides grapes. Vitis vinifera, (Genus species) main grape When making wine from fruit other than grown world wide for grapes it is often necessary to add sugar, water wine, native to Asia and nutrients to achieve a fermentable Minor & Caspian Sea. product that will make a stable wine. Zinfandel 7 8 Vitis vinifera Native American varieties V. labrusca, Concord Vitis vinifera is by far the most widely (grape used in Welch's), planted variety in the world and accounts Delaware (foxy, artificial for the vast majority of wine produced. grape flavor) Muscadinia rotundifolia However it is not suited to every climate. Scuppernong (fruity flavor) Vitis aestivalis, Norton (delicate flavor) Concord 9 10 Which grapes to use for wine? Grape Varieties French American Hybrids, attempts to mix The different varieties winter hardiness and disease of vinifera grapes are resistance with good flavors analogous to the (with limited success). different varieties of Examples are Maréchal apples. Foch, Aurora, Chardonel, All of these are the Seyval Blanc, and Vidal same species, Blanc, mostly grown in the Malus domestica . Eastern US. Vidal Blanc 11 12 Viticulture 2 Grape Varieties Handout Grape varieties Estimates are there are more than 10,000 In the links section of the website is a handout cultivars of vinifera. Here in California we that lists varieties and their pronunciation. grow only a few commercially, six varieties make up 80% of production. We will discuss grape varieties in detail in upcoming lectures. Clones/Budwood A clone is a genetically identical group of plants from a single mother plant created by vegetative propagation. 13 14 Clones continued Clones & Quarantines Most Vinifera Clones have subtle differences Interest in the late 1800s in producing new in yield, flavor and aroma. The same clone varieties led to the importation of native will often act differently in different vineyards. American vines into France and with them their diseases phylloxera & powdery mildew. Species: Vitis vinifera Today import quarantines seek to prevent new Variety: Pinot Noir pests. Clone: 667 (France) 15 16 Above ground Phylloxera Phylloxera A sap-sucking insect related to aphids that In California it does feeds on vine roots and causes galls to form, not have a flying stage robbing vigor until the vine is killed. (conditions too dry) so it reproduces asexually. This means there is less genetic diversity and it does not spread as quickly. 17 Below ground 18 Viticulture 3 Rootstocks Rootstocks Necessary where phylloxera is present (or is likely to come). They are usually crosses between North American native species such as V. berdlandieri, V. riparia and V. rupestris. These species evolved in the presence of phylloxera so they are naturally resistant to the pest. V. rupestris 19 20 Grafting Grafting The process of grafting a vinifera (wine grape) T-budding, on a young wine variety onto a resistant rootstock, can be done after planting (chip budding or T-budding) or "bench top" before planting). Chip Budding 21 22 Grafting Grafting bench top T-budding, grafts fit like a can also be mortise and used for tenon joint, changing best method variety of for small scale mature vines. growers. 23 24 Viticulture 4 Phylloxera & AxR-1 Phylloxera & AxR-1 This was a huge problem AxR-1 worked well for many years but in the 1980's a new type of more virulent phylloxera because 85% of California was found in CA, Biotype B. was planted on AXR-1 and AxR-1 was a popular rootstock because it Biotype B spread very produced vigorous vines and was disease rapidly. resistant. It was known not to be very Replanting solved the resistant to phylloxera but it was incorrectly problem but was expensive thought to be adequate for the conditions in due to the cost of replanting St. George AXR1 California. and lost production. 25 26 Types of rootstocks Rootstocks Continued St. George, used to be popular, produces You should select the rootstock to fit the vigorous vines (old vine Zin) vineyards terroir (environmental conditions) 3309, 3916, Harmony, Freedom, 1103 just like you do when you select the scion. Paulsen, & 5C are currently popular. 5C is Also harder for pests to attack many different good for wet conditions, 3916 is resistant to oak rootstocks. root fungus. As an Example, 420-A does well in Lake 110-R SO4, & 420-A Low vigor, can be useful County for Sauv Blanc, but not as good for in high vigor situations. Napa Cab Sauv. Link to rootstock chart on website 27 28 Own-rooted Vines The Growing Season Grapevines continue to be grown on their We will learn about own roots in areas where phylloxera is not how vines produce present such as Chile and Washington State. grapes by following Strict quarantines keep the pest out, but the vines through the growers in these areas are always nervous yearly cycle of the about it being introduced. growing season. If you don’t have phylloxera, own-rooted is the best method. 29 Bud break, early March 30 Viticulture 5 Fruit bud formation Cane Buds form in the axial crotch of the leaf as the Cane & bud cane grows in the spring. Buds contain morphology Lateral cluster primordia. The buds that will produce this year’s crop were formed during Petiole the previous year’s growing season. Primary shoot The fruitfulness of buds (# of clusters on shoot primordia ) depends on exposure of light to the Secondary shoot canes when they are formed “Sun Canes”. Tertiary shoot 31 32 Budbreak Frost Damage Frost can damage or kill young shoots. If they Here in Sonoma County budbreak usually are damaged secondary & tertiary shoots inside occurs in late February to early March. the buds take over, but they are not as fruitful. Temperature Bud break is temperature dependent on soil temperature. Wet soil warms up more slowly so during rainy years bud break delayed. 33 34 Frost Damage Frost Protection The danger is usually over by mid May Hillside vineyards have natural air drainage depending on the region. The low parts of the and usually do not need frost protection. vineyard are most susceptible. Above Freezing Below Freezing 35 36 Viticulture 6 Frost Protection Frost Protection Wind machines, Shur Farms Fan & with or without Vineyard heater heaters, stir up inversion layer in air mixing warmer upper air with cooler ground layer air 37 38 Frost Spring Cultural Practices Protection Spraying for control of rot and mildew Mowing or tilling Sprinklers, as long as ice is Herbicide application forming on the Shoot positioning new shoots their Suckering temp will not fall below 32ºF. 39 40 Bloom Set & Shatter Bloom Set & Shatter Occurs about 8 weeks after bud Set (berry formation) Occurs when pollination break (May/June). achieves fertilization & seed development. Full Bloom Refers to the opening clusters result from about 25% to 35% set. of the grape flower. Temperature dependent, it Influenced by: takes about 8 to 10 days over Weather favorable conditions (warm, Variety, Merlot can have difficulty setting even temps). Varieties bloom Excess Nitrogen (fertilization) causes poor set in the order that they ripen in the fall. Rootstock, 420-A used to achieve better set 41 42 Viticulture 7 Bloom Set & Shatter Bloom Set & Shatter If these events happen over an extended Good set period of time ripening is uneven. Too hot weather causes shatter, too cold weather prevents bloom. Shatter, the detachment of unfertilized berries from cluster, is what happens when the flowers don't set. Poor Set 43 44 Berry Development Berry Development Green Stage from set to the beginning of ripening. Berries slowly increase in size, sugar Véraison Start of level and acid level. Sugar gets to about 3° Brix, ripening. Color malic & tartaric acids are synthesized, acid level change occurs, berries is at its highest. soften, begin accumulating sugar, a very abrupt change. Grapes 3 weeks after vay-ray-ZON vs. bloom ver-eh-shun 45 46 Photosynthesis Berry Development 6CO2 + 6H2O + sunlight chlorophyll C6H12O6 (sugar) + 6O2 Ripening Berry swells & softens, sugars accumulate in berries from leafs from photosynthesis. Photosynthesis stops if it gets too hot to conserve vine water. 47 48 Viticulture 8 Ripeness Tartaric and Malic acid levels are stable until ripening begins. Acidity diminishes after véraison primarily from dilution. Malic acid Leaf is respired (used in berry metabolism) Diagram especially in hot weather. Malic acid is can be metabolized at night without photosynthesis.