2/10/2014
Tonight’s Lecture
Review preliminary 2013 Grape Crush Report Harvest & White Crush Harvesting grapes And Fermentation Crushing Pressing Wine 3 Settling and pre-fermentation operations Introduction to Enology Barrel vs. tank fermentation White grape varieties
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2013 Grape Crush Report 2013 Grape Crush Report This report is compiled by the State The report divides and shows the state into 17 production levels and grape growing pricing for all of the districts and grapes (wine, table, collects data by and raisin) produced district. in the State.
2013 Grape Crush Report 2013 Grape Crush Report
Very important The preliminary report is published February information for 10th and the handout includes information on growers and pricing from table 10 of the report. wineries alike. A link to the website for the complete report is Sonoma County at the class website. is district 3 State wide price/ton is very low compared to Sonoma County. Final report with updated figures is released in March.
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2013 Grape Crush Report ~ Highlights CA prices Yield up 7% down 4%
Sonoma prices up 3%
White vs. Red Winemaking
The two methods are not mutually exclusive. White grapes make white wine and visa versa, (obviously), but their processing is also different. Although they are inherently different, both red and white winemaking use a lot of the same equipment and processes in slightly different ways.
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White Wine Styles Efficiency vs. Quality
White wines are generally more focused on Many times the best method for making fruity flavors than reds, and are usually not quality wines is not the most efficient. aged for long periods of time. The right method for each wine depends on Whites have less phenolic compounds its style, target market, and price. (responsible for color, astringency, and bitterness) Winemakers must weigh both factors before They can be made with no, low, or a lot of oak making winemaking decisions. character. They can be made dry, off-dry (slightly sweet) or very sweet.
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Grape Harvesting Hand Harvesting Harvest The first part of this lecture equally The traditional applies to both whites and reds. method of picking, Picking Hand vs. Mechanical where crews of several Both methods have advantages and to several hundred disadvantages and each work for particular pickers are hired to go situations. through the vineyard and pick the fruit using picking knives or sheers.
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Hand Harvesting Hand Harvesting Advantages: Versatile, can pick on any terrain or trellis system. Selective, picks only the good fruit, skips rot, mold, second crop etc. Less damage to fruit (very gentle). Less up front cost compared to mechanical harvesters, but you can rent mechanical Hillside harvesters. vineyard in Monterosso Italy
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Mechanical Harvest Mechanical Harvest Done with picking machines that shake the Advantages: clusters & berries off the vine. May become the Delivers cool fruit (picks at night with lights) industry standard due to labor shortages. important for white grapes grown in warm areas. Fast, can do 100+ tons a night no problem. Gives you de-stemmed berries (wineries don't pay for stems). Cheaper about $175 an acre compared to $750+ for hand. Easily available, you don't have to find pickers.
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Mechanical Harvester
Picking mechanisms
Closure Wings
Interior view of mechanical harvester 20
Hand vs. Mechanical Night Hand Harvest
Hand is generally better for high end winemaking. Best quality for That being said, mechanical harvest done well but it is more delivers better grapes than hand harvest done expensive than poorly. mech. harv. More important to whites than reds
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Night Hand Harvest Second Crop This is when fruit clusters are There are logistical formed on a lateral and quality shoot. Small quantity advantages to and less flavor than first getting cool grapes crop. first thing in the Usually not picked AM. Pickers like it commercially because of but for vineyard economics, good source managers it can of grapes for home Night harvest with headlamps mean longer days. winemakers.
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Fruit Delivery 1/4 to 1/2 ton bins good Fruit Delivery compromise not too much Lug Boxes 40 to 60 damage to fruit but a lot easier pounds, provide the to handle mechanically, very least amount of although it does require some damage to the fruit specialized equipment. so they are great for Bins are towed on trailers sparkling wine, but through the vineyard then are a logistical loaded onto trucks, 1/4 ton MacroBin headache. bins can be used for less bruising.
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Fruit Delivery
Gondolas, 2 ½ to 6 ton trailers, traditional California method, loaded in the vineyard towed behind a tractor then transferred to a pickup for trip to the winery. They are dumped in hopper with hoist. Not as popular as they used to be. 27 28
Bins on Trucks (Valley Bins) Bins on Trucks (Valley Bins)
2 to 3 ton bins. Similar to gondolas This is a good but are loaded on compromise the back of a semi. between Requires a forklift quality & in the vineyard, one efficiency. semi truck and Used for both trailer can haul 20 mechanical and to 25 Tons. hand harvest.
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Large Bins Field Crushing
Crushing in the Field Lets you add SO2 5 to 10 ton Bins, quickly (if you want to), and crushed grapes these stay on the need less space for transport, not often used truck and the fruit is dumped into because of poor quality control. them in the Can be used by home winemakers who do vineyard. Double not have enough lug boxes. (crushed fruit dumping means takes up less space). less gentle than Valley Bins.
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Inspection and Weighing Inspection and Weighing Load of fruit is weighed and the weigh tag is filled out; sometimes this is done away from the Visual inspection for variety (in 1980’s one winery. Valley bins can be weighed as they are winery crushed more Zin than was grown in the loaded on trucks. entire state) and MOG (Material Other than Grapes); important at large wineries where there More about weigh is less contact with growers. tags in the lecture If the grapes are mechanically harvested it can be on wine law. difficult to tell what the variety is because the fruit is crushed.
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Inspection and Weighing Inspection and Weighing
Lab Analysis of the load, done from a stab, It is very important that this analysis is must line, or press sump sample, analysis is accurate because you have to know what you similar to a vineyard sample. Check Brix, pH, are getting and the growers pay is often TA, temperature, Brix measurement done in determined by these numbers. detail in lab and wine chemistry lecture. Analysis is only as good as the sample. This is sometimes done by a state agency or third party inspector to avoid bias.
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Sugar Shack Sugar Shack
Truck sampling at a large winery Getting a stab sample from a 5 ton bin of mechanically harvested fruit
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Inspection and Weighing Unloading the Fruit
Truck sampling is more rigorous at large wineries where there is less contact between the grower & vintner. Ideally at smaller wineries you should know what you are getting before the grapes are picked. Rejecting a load after harvest is sometimes done, but it is always a hassle for all concerned. 2-Ton Bin 5-Ton Bin
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Unloading Fruit is dumped into a hopper and transported by either augers or Receiving Hopper conveyor belts. Augers are easier to clean, and belts are gentler to the fruit. Progressive Auger
One flight
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Sorting Hand Sorting At high end wineries sorting Sorting can be is done after the done before or fruit is received after crushing. to remove After crushing MOG and poor is good for reds quality fruit. because you can remove stem “jacks”.
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Automated (optical) Sorting Automated (optical) Sorting
Automated sorters use cameras and jets of compressed air After sorting to remove MOG; they can process up to 10 to 15 Extra protein in tons/hour. Green Beans
Cull
Crushing and Crushing and De-stemming Crushers have rotating De-stemming bars inside a perforated The equipment for this is the same for whites cage to de-stem the or reds but they handled slightly differently. grapes, then a set of Tonight we will concentrate on how they are rollers to crush the fruit used for white wine making. Crushers have a sump Traditionally grapes were trodden and then underneath with a high pushed through screens. The first vintage of capacity pump that can Fern Cellars (my old homemade wine) was handle high solids to done with a garbage can and a bike basket. Stemmer-Crusher transport the must.
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Stemmer-Crusher Why Crush or De-stem?
Crushed grapes are easier to move (pump) They drain better and fill presses more evenly Reds fermented on stems can pick up a phenolic "stemmy" taste. Crushing makes the juice accessible to the yeast.
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White Wine Crush Must Now that the grapes are crushed, the resulting Now we will be dealing with white wine combination of juice, skins and seeds is called processing only. Reds get their color from fermenting on the skins and whites are separated Must. Must is approximately 80% Juice, 16% from the skins (pressed) before fermentation. Skins, 4% seeds by weight, this varies a lot by variety, vineyard & vintage.
Crushed Muscat
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Dejuicing Dejuicing
The act of separating the juice from the must Static dejuicing tanks (DJs) usually hold without any kind of pressure (besides gravity) is one press load, originally designed for skin called dejuicing. This step is not needed for contact when it was trendy (now becoming whole cluster pressing and it is optional for popular again). crushed grapes. They also act as a surge tank for matching a If done properly it will improve quality and continuous process (crusher) with a batch process (press). ease processing. You loose much of the advantage if the grapes are mechanically harvested.
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Dejuicing Tanks (DJs) Skin Contact
Pre-fermentation skin contact of 4 to 24 hours will increase varietal character in white varieties such as Sauvignon Blanc and Muscat. Skin contact of whites before pressing will affect color and increase phenolic content.
Screen inside tank
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Dejuicing Mechanical Dejuicer
Mechanical, Often an incline wedge-wire screen in line to a press. Allows for separation of 50% to 80% of the juice. Works very fast and gives high yield, but lower juice quality due to high solids & phenolics due to sheering action. Works well on mechanically harvested grapes.
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Whole Cluster Pressing Whole Cluster Pressing
But.... you don't have to crush whites. Advantages: Clusters have stems for a natural This is where white grapes are loaded whole press aid and the fruit is not as macerated so cluster into the presses without being there is less extraction of phenols from skins. crushed first. Excellent quality but more Generally results in difficult, it works well with delicate white higher quality wine. varieties and sparkling wines.
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Whole Cluster Pressing Temperature Factors
Disadvantages: Cuts press capacity by 1/2 Temperature affects the rate of oxidation of and extends press cycle, labor intensive phenols (browning) done by enzyme because the press is more difficult to load. tyrosinase (polyphenol oxidase). Must is more More costly because of the extra presses you sensitive to temperature than grapes due to need to buy, good for sparkling and high-end the rupture of the cells. Controlled by: white wines because of the low level of Morning picking is used to keep grapes cool. extraction from the skins. Cooling tunnels and must chillers Temperature also affects the rate of growth of spoilage organisms.
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Enzymes Enzymes
Enzyme addition Pectinases are enzymes Settling enzymes aid in juice clarification that can be added to the must in the DJ that and are added to the juice after pressing or break down Pectins (the substance grape skins are during skin contact. made of that hold in the juice). Added on skins gives better yield, added on Increases yield of free run, frees sugar and juice aids in clarification. other flavor compounds in the pulp, needs 2 This can result in better aroma and cleaner to 4 hours contact time. juice but can also increase quantity of lees. Counter fining with a little gelatin helps compact the lees.
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Pressing Mechanical Presses Pressing is the act of squeezing the must Vertical basket press, against a screen that separates the juice from The oldest design, the skins and seeds. gentle and slow used Whites are pressed before Fermentation most by home Reds are pressed after Fermentation winemakers & small Two general types of presses: Mechanical high-end wineries. Presses & Pneumatic Presses Operated by screw or hydraulic rams.
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Mechanical Presses Mechanical Presses Basket presses are still Home winemaker used by some versions sometimes commercial wineries. they have a bladder that can be pressurized with water to squeeze out the juice.
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Horizontal basket press Horizontal basket press
Loads and unloads Horizontal basket press video easy and has big doors for whole http://www.cognac.fr/cognac/_en/mod cluster pressing, lots ules/cognac_pressoir_plateaux/pressoir_ of O though. Has 2 plateau.html high mechanical pressure 6 ATMs.
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Continuous Presses Measuring Pressure Belt and Screw type, high speed and high solids & There are several ways to measure pressure, phenols. Press fractions both US and Metric are possible; best suited to 1 Atmosphere (atm) is equal to the air bulk wine processing. pressure at sea level (approximately) 1 atm = 14.7 PSI (pounds/square inch) 1 atm = 1 bar 1 bar = 1000 millibars
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Pneumatic Pneumatic Presses Presses Membrane, also called tank, presses made Bladder Horizontal by Deime, Vaslin/Bucher, and Willmes; these basket can be hard to are the workhorses in premium wineries. load drains well They are programmable and can do central because it pushes to (Axial) filling (this increases solids). the sides, lots of O2 Complicated and expensive. (Oxygen) pickup. Complete cycle takes from 1.5 to 4 hours, the slower you go, the more gentle the process.
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Membrane Press Membrane Press
Interior of Tank or Juice Pan Membrane Press Tank or Membrane Press, good quality and high yield
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Membrane Press Operation Juice Quality
Press Fractions The highest quality juice comes from the middle layer of the berry. It is the first juice that comes off during dejuicing or from the beginning of the press cycle. This is called the free run.
Filling Pressing Emptying Press
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Berry Diagram Juice Quality & Press Fractions
Free Run it makes up about 75% to 85% of the juice. The free run is usually kept separate from the press juice (the second fraction). The change is evidenced by a drop in sugar, a rise in pH and a darker color in the juice. Chosen by gallons pressed, pressure, or by taste.
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Juice Quality & Press Fractions Press Aids
In big (low quality) wineries the separation Press Aids Can be added to aid dejuicing of fractions is often not done. and get better and faster yields by breaking up For homemade wines it is not as important the cake and allowing juice to exit. because you usually do not press hard Rice Hulls or stems can be added back. enough to get a big difference between free Mainly needed for "slippery skinned" varieties run and press. like Chenin Blanc, Sauv Blanc or Muscat. Not needed for whole cluster pressing.
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Press Aids Sulfur dioxide, SO2
Sulfur dioxide or SO2 Is a preservative that inhibits destructive enzymes and undesired Rice hulls used microbes. It can be added to the juice as a press aid coming out of the DJs or the presses at a level of 30 to 50 PPM. This is a big topic that we will go into much more depth in a later lecture.
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2 Sulfur dioxide, SO2 Sulfur dioxide, SO
Passive Oxidation combined with PF SO2 In certain cases passive oxidation is used to uses no SO2 but lots of inert gas (N2 or CO2) try and improve white wine quality, oxidation blanketing, some oxidation occurs during causes phenols to turn brown and loss of pressing and crushing and the must turns fruity compounds. brown. The oxidized phenols settle out leaving good, This is the called “Post Fermentation SO2“ PF SO method for white wines (usually stable color after fermentation. PF SO2 helps 2 ML fermentation to complete. Chardonnay). Good for whites aged in oak such as Chardonnay & Viognier.
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Sulfur dioxide, SO2 Sulfur dioxide, SO2
Protective SO2 added before fermentation It is a good idea though to keep SO2 as low as at the press sump or in the tank. Stops possible, and the PF SO2 method has a lower oxidation before it gets too far, poorer color level of SO2 at bottling. Neither method is best, as the wine ages but more fruitiness. it is mainly a stylistic consideration.
Good for varieties with a lot of fruit character Generally speaking, PF SO2 gives you better such as Pinot Gris, Sauvignon Blanc, Riesling, color, body and ageability while the SO2 before Muscat, and Gewürztraminer. fermentation method gives you more fruity flavors.
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Sulfur dioxide, SO2 Juice Clarification Organic wines vs. Organic Grapes There Purpose is to remove excess solids in the is a distinction between the passive oxidation juice. Solids are soil, fragments of stems &
and the no SO2 at all (organic) method, in all skins, fibers from pulp and insoluble proteins. wine some SO2 is produced by yeast. If it is left in the juice it can leave a high Organic wines must also be made from solids character (musty, chalky, H2S, low organically grown grapes. fruit). Whole cluster pressing leaves 3% to 8% In the EU it is OK to add SO2 to Organic wines. Free run with crushing gives 10% to 20%
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Juice Clarification Juice Clarification
You want about 0.5% to 1% solids in clarified Tank Settling Juice is placed in tank and juice before fermentation. Less than 0.5 % allowed to settle for 12 to 72 hours, then clean you can get stuck fermentations from low juice is decanted or "racked" off. Lees are nutrients. what is left behind (about 10% of volume). This corresponds to between 100 and 600 Lees can be filtered through a lees filter nephelometric turbidity units (NTU). We will (covered in the wine processing lecture). learn more about these in a later lecture.
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Juice Clarification Racking a Tank
Grape juice before and after settling 93 94
Racking a Tank
Racking Door Racking a Pump Tank
Racking Lees at bottom of tank Valve Hose or transfer line
Bottom, or transfer valve
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Racking a Tank Settling in Large Tanks
Racking Arms, these Settling is more efficient in smaller tanks. In fittings allow you to tanks over 15,000 gallons it can take too long rack the wine clean to settle so large wineries often employ right down to the centrifuges or filters to clarify juice. level of the lees Mechanically harvested fruit and soft-skinned without opening the varieties can have higher solids and take tank door. longer to settle.
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Centrifuging Juice Clarification by Floatation Two types: (we will go over how they work in the wine processing lecture). These used to be Relatively new technology for wine; it much more popular. separates solids by floatation using nitrogen Decanter Centrifuge input is 25%, output is gas combined with pectinase enzymes. 2%-5%. Takes about 6 to 8 hours and can result in Desluging Centrifuge does better with lower very clean juice. solids (> 10%), but cleans it up better so is more common because it is more versatile. It is good at stopping fermentations (expensive and loud).
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Juice Clarification by Floatation Operations done during settling
Enzyme addition to help with settling (optional)
SO2 addition (optional) to protect it from spontaneous fermentation. Cooling jackets are turned on to help preserve the juice (50 degrees). Analysis for nitrogen, TA (titratable acid), pH and sugar is done and the tank is gauged. eflot from AEB Juice after treatment
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Fermentation vessels Operations done after racking Stainless Steel Tanks After settling/clarification the wine is Stainless is great for cleaning, durability, and transferred into its fermentation vessel. temperature control. If needed acid addition is done at the end of White wines are usually fermented cool (45º - settling when the juice is racked. 55º) to preserve the floral & fruity aromas. Cooling jackets are set to fermentation For a compound to have an aroma it must be temperature (45 to 60ºF.) volatile (able to evaporate) and if a Yeast is added (if not using the native yeast) fermentation is hot many of the aromatic components evaporate away.
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Stainless Steel Venting tanks Tanks Tanks must be vented before emptying or filling. Top manway Double wall cooling jacket Racking Door Thermo wells Racking valve Bottom Valve
Pressure relief valve
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Venting tanks Barrel Fermentation
Barrels, used for some white wines gives a Atmospheri “toasty” flavor. Barrels usually ferment at a c pressure higher temperature so the juice ferments causes more quickly; small volume helps them to unvented settle. Harder to clean and control the rate of tanks to fermentation. collapse. Usually inoculated (started) in tanks and when fermentation starts they are sent to barrels.
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Barrel Fermentation Other fermentation vessels Start the juice to be fermented in a tank, Wooden Tanks, Similar to barrels but inoculate with yeast, and then just as it is usually don't get toasty effect because of starting to ferment (1 or 2 days), transfer to lower surface to volume ratio. barrels. For home winemaking fermentation vessels, Since barrels do not have cooling jackets it is olive drums, barrels, plastic picking bins, beer best to chill the juice to 40 to 45ºF the night kegs, glass carboys. You need an wide- before filling. opening top for reds but not for whites. As the barrels are being filled it is important to mix the tank occasionally to keep the yeast homogenized. 109 110
Filling a fermentation tank During When filling a tank for white juice Fermentation fermentation you can only fill it to about 90% capacity to allow room for foam. Monitor the wine The amount is dependent of type of yeast and daily checking for: temp of fermentation. Temperature Barrels have to be left down 10% to 20% Brix, because of the fact they ferment faster and Sensory (smell) generate more foam than wine fermented in stainless.
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After fermentation After fermentation you have wine! After fermentation the yeast settles out to the As we discussed last week, the rate of bottom the tank and the wine is racked off fermentation depends on the type of yeast, (yeast lees are much more compact and are amount of nutrients, starting Brix, and most usually not filtered). importantly the temperature of fermentation. After the yeast has settled in one to two It usually takes about 3 to 5 weeks for a weeks the wine can be racked off the lees. white wine to go dry. 10 days to two weeks if it is in barrels.
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Sur lie aging Advantages of Sur lie aging
Barrels can also be racked off the lees, or they Stirring (batonage) is intensifies the flavor can be toped up and left in the barrel to age effect. sur lei, pronounced soor-lee. Yeast lees are different from primary lees. Gives the wine a “yeasty" character and adds viscosity. stirring barrel lees The presence of yeast also helps protect against oxidation.
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Sur lie aging Blush Wines Different types of stir rods are available, Blush wines are white or pink wines made some are curved to fit from red grapes, White Zin is the classic in-between barrel example. racks. They are made in much the same style as a white wine and the grapes are handled very It takes about 10 days for a wine barrel to gently and there is a little skin contact as settle so stirring is possible to keep the color extraction to an absolute minimum. usually done every 1 to Stir rods 3 weeks.
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Blush Wines Blush/Rose Wines This is the way that fine sparkling wines in Rose wines are pink wines that are made the Blanc de Noir (white from black) style are with limited skin contact or by mixing a red made. White Zin (Chateau Cash Flow). A and a white wine together to form a pink good wine for beginning wine drinkers. wine. They are pink in color, but made like a white They are also made by fermenting a light wine. colored red variety on the skins and pressing it very early. Serving suggestion Generally taken more seriously than blush wines.
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Rose Wines White Grape Varieties
Roses can also be made from “bleed-off” or We will cover some of the most popular saignée (pronounced san-yay) from red white grape varieties that are grown in fermenters when 10 to 15% of the juice is California. Next week we will cover red removed to concentrate the flavor of the varieties. must that is left behind (higher skin/juice The % planted numbers are a little different ratio). than the handout. We will talk more about saignées next week.
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Next week
Red Crush & Fermentation Lab this week is processing equipment for white wine, and small scale fermentations.
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