Chapter 5 CSW Test Winemaking process

Why is it vital to keep the grapes cool in the “pre-fermentation” stage (after picking)and begin the process winemaking asap?

Because keeping them cool and covered minimizes the oxidation that starts as soon as the grapes are picked. The unbroken grapes begin transforming into raisins and the broken grapes begin unpredictable and problematic fermentation. The addition of sulphur in the pre-fermentation process via SO2 inhibits growth of yeast and bacteria reducing the possibility of premature fermentation. Prefermentation is also called “the crush” even though it covers the short period before the grapes were crushed.

What is the difference between crush and press

Crush involves the skin of the grape breaking and the juice flowing but no pressure beyond gravity is employed. The pressing is gentle press of the grapes to extract juice. To much force can introduce to much tannin or astringency from the skins.

What is free run juice?

Juice that runs free from the crush process which is primo because it’s high in sugar and low in tannins.

What is the cake of dried skins, sees, etc left over after the pressing is completed called and what can it be used for?

it’s called the Pomace and it can be used to make Marc or Grappa.

What is the Must?

The Must is the grape juice and destined for fermentation.

Why would you have to adjust the must before fermentation?

If the sugar is too low because the grapes didn’t reach maturity in a marginal climate, or if the acid is too high the must can be adjusted in a couple of ways. You can add acid (generally Tartaric) in a process called Acidification that shouldn’t affect the taste but will bring the TA up or you can add sodium Bicarbonate to bring acid down or Chaptilize (add sugar) to raise the potentatial alcohol levels in grape juice with insufficient sugar to do so as is. Note that Chaptilization is not a method to make wine sweet.

What is Debourage or Juice Settling?

When you let the juice sit for a day or two to let the solids to settle or for a must-adjustment to integrate, or for more grapes to arrive to be vilified with what you have.

What does it mean to catalyze?

To make a chemical reaction happen

What is an Enzyme?

An enemy is an organic substance capable of causing a chemical change in yeast

What happens in Fernetation (in basic terns)

Yeast cells attack sugar molecules and break them apart to release energy, some of which is heat. What remains is Ethyl alcohol and CO2. After the yeast cells have eaten through all the available sugar in the must. Generally speaking 90% of sugar is fully consumed when fermentation stops, not 100%

What is Natural Fermentation and what are the pros and cons

Natural fermentation is when you let the environment introduce a native yeast to the wine as opposed to choosing one intentionally. Pro, easy, can work in areas with well-defined styles, Can also introduce yeasts that leave bad smell or don’t fully metabolize the sugars.

What is inoculation in the Winemaking process?

When you inject the must with a cultured yeast to get it off to a fast start giving it an advantage over any natural yeast present. This is the opposite of Natural Fermentation.

What is the idea temperature for fermentation of White Wines?

50-60 degrees to retain delicate fruit and floral aromas.

What is stuck fermentation?

When the temperature exceeds 100 degrees F the yeast die off and the must stops fermenting. This is very difficult to reverse and is the #1 cause of “stuck fermentation.”

When does fermentation end and what are thee causes

It ends when:

1. all the sugar is depleted. (never really all)

2. If alcohol content reaches 14%+ (may still be some residual sugar)

What is Malolactic Fermentation (MLF)?

Not actually a fermentation but a conversion that can happen simultaneously with the primary fermentation or after it. Can more accurately be called Malolactic conversion. Happens with the introduction of Lactic Acid bacteria that converts the Malic Acid (sharp) into lactic acid (soft). An ester called Diacetyl which is a byproduct of MLF which imparts the buttery flavors

Besides Chardonnay what wines go through Malo

Chennin Blanc, Viognoier,

What is Lee’s contact all about

Sur lie Aging (on the lees) is when you let the wine sit in the lees which is the dead yeast cells and other solid particles which sink to the bottom. As the yeast cells decompose, they lend a yeasty aromas and a creamy texture. If the lees are stirred it is called battonage

Why is Sulphur level checked after fermentation?

To prevent microbial spoilage or browning. VERY important if there is any RS in the wine.

What is Clarification?

The process of making cloudy wine clear. Can be done through Racking, Fining,Filtering or centrifuge. Racking is the process of letting the sediment settle at the bottom and then drawing of the top to a new vessel leaving clear wine after several iterations. Or Fining, which is using a material that has an affinity for the thing you want to remove so that it binds to the sediment and sinks to the bottom. Finally filtering can remove everything down to the level or bacteria but can also remove flavor and life from a wine. Centrifuge uses accelerated gravity to remove solids.

Why do people barrel age white wines sometimes?

Aging in oak barrels allows for a slow oxidation and, when new, a vanilla flavor (or wood, coconut, toast, etc).

What is cold stabilization?

If a wine has a lot of Tartaric Acid and it gets cold, the Tartaric Acid may precipitate out and form a solution and then crystalize on the cork area (wine diamonds) to prevent this cold stabilization involves lowering the wine to 25 Degrees for 1-3 weeks and racking off the predicates. An alternative is finely ground Sodium Bitartrate.

What is the order of steps for the wine making process

Grapes Arrive

Sort - Crush - De-stem

Grape Pressing

Must Adjustment - Juice Setting

Fermentation

Yeast Inoculation - Temperature Control

Post Fermentation

Lees Contact, MLF, Clarification, Aging, Blending, Cost Stabilization.

How is must adjustment different for red wines?

If legally permitted the winemaker can add tannins if the grapes are lacking, by adding in stems to the must or adding tannin powder

What is Maceration?

The period of time when the juice remains in contact with the skins which hold the phenolics and color components. Can last from a few days to a few weeks or longer. Longer soak leads to more extracted wines. More extracted wines can require more aging to really shine. Biggest decision in winemaking is how long to macerate. Shorter maceration times generally results in wines that are ready to go at a younger age.

When it comes to Maceration what is the difference between varieties like Cab SaV and Syrah v Pinot Noir?

The first two have a lot of color that is easily pulled from the skins whereas Pinot does not and will require a longer maceration period.

What is a cold Soak

When the must is dropped below 55degrees to inhibit and postpone fermentation

What is the difference between a cold soak and maceration during fermentation (like normal)

When fermenting (higher temps) there is alcohol in the mix which is a good solvent for color and phenolics. When in cold soak, there is still maceration but only in water so less pronounced.

What’s the difference between fermenting red wines and white

Main difference is the presence of grape skins in the must.Also, if you’re going to ferment on the skins, it’s easier to do it in a big stainless steel container that’s easy to clean.

What is cap management (red wine making)

When the CO2 that’s produced in fermentation forms bubblers that push the grape solids to the top forming a dense cap which must be broken up by the wine maker to ensure proper phenolic extraction. Also, if not done, Acetobacter might form creating excess acetic acid and trapped CO2 could even blow the cap off.

Describe the four methods of cap management

Punch down: Pushing the cap back into the must

Pumpover: Pumping juice from the bottom over the top of the cap (Remontage in French)

Rack and return: Pull the liquid into another large tank and then spraying it over the cap which has now sunk, to add more aeration than a standard pump over. “delestage” in Frenchn

Rotofermention: When automated paddles move the must around on a timer preventing the formation of a cap - Tre modern! Eliminates the need for all other cap management.

Why are red wines fermented at higher temps than whites, generally?

1. Less necessary to capture delicate floral aromas than in whites which use cold fermentation

2. Warmer temps allow more phenolic extraction,

What red wines might you ferment at 60 degrees and what around 85-95 degrees

Pinot Noir v Cabernet

What is extended Maceration?

When you let the must sit with the solids for a period after fermentation is complete.

Do red wines also use MLF?

More than whites. High acidity bad in most reds. MLF can also be used to produce a microbial-stabile wine by reducing malic acid.

What happens in the pressing for red wine?

Pressing happens after the wine has been racked off. The Solids are pressed which leaves a very tannic and dark colored wine which can be mixed back into the racked wine to add complexity and color.

What is clarification for red wine?

The wine is moved to a separate tank and racked one or more times. Then it can be fined or filtered but that is done less with red wines as it removes phenolics too.

What’s the purpose of aging red wine in wood barrels.

The barrels let in a limited amount of oxygen which seeps through the oak and into the wine. Once there, it helps the tannin molecules combine with each other (polymerization) into longer chains of tannin which are softer on the pallet than short hard tannins found in grapes.

Young/New barrels also add a toasty vanilla flavor. Finally Oak can add complexity to a well-balanced wine

How long do new oak barrels impart flavor to the wine they store?

1-4 year. After that that, it’s mostly gone. Smaller the barrel, the more oak flavor than larger ones as there is a higher ration of oak to wine.

What are the two primary sources for oak barrels.

France and the USA> French oak is considered more subtle and refined in flavor. American oak is more assertive and less expensive. There are also barrels available from the Baltic States, Canada and Russia.

What are the various barrel options?

Shape, Size and Type of wood, then Light, Medium, Heavy Toast levels of char

How much is a new French oak barrel

$1300 ±

What is Carbonic maceration

What is Carbonic Maceration?

Alternative method of red wine making using no bacteria or yeast. By putting grapes in a container and bathing them in CO2. In this environment enzymes in the grapes will break down the sugar and begin making alcohol. Then, generally the wine is fermented like any other. The result is light tropical wines, think Beaujolais Nouveau.

What are the ways Rose in made starting with the most common.

1. Limited Skin contact where the red grapes are finish fermenting away from the skins

2. Saignee Method When a small amount of juice is siphoned off after limited skin contact. Remaining juice becomes red wine.

3. Direct Press Method (Provence) Grapes are crushed immediately after harvest and then pressed after a very short maceration resulting in a light salmon color

What are different ways to make desert wine?

Botrytis Cinera, Late Harvest, Dried Grapes and Freezing

Botrytis is a fungus that strips water from the berries leaving concentrated sugar

Late harvest means letting the grapes sit past peak ripeness and continue to gain sugar (thought they loose acid so best done in cool climate (Loire/Sauternes)

Partially dried grapes like in Amarone, a style seen throughout the mediteranian.

Freezing/Ice Wine is popular in Canada and Germany on other cold climate area. Growers leave grapes on vine until they freeze and then pressed immediately. Riesling and Chenin Blanc and Gewurtztraminer are often used.