Brewing Country Wines Benjamin F. Lasseter, Ph.D.

Chair, Hampton Roads American Chemical Society

What is a “country wine”?

• An alcoholic beverage produced at home, instead of commercially

… possibly using grapes. Not always.

… the result of a very complicated chemical and biological process…

…that can be done with Medieval technology.

Alcoholic Brews

Beer

• Lagers

• Ales

Wine

• Fruit Wines

• Vegetable and Herb Wines

• False Meads

True Mead

• Honey Mead

• Methyglyn, Melomel, etc.

Other Fermented Substances

Whisky

Sake

Mash Kefir, Kumis, Viili

Various Poisons

Exotics

How starch becomes sugar

How sugar becomes pyruvate

How pyruvate becomes alcohol

Humans can’t do this step.

And that’s the SIMPLE model of how starch becomes alcohol!

The more complex version: How starch REALLY becomes sugar

And starch is not simple

The sugars in starch vary in different species.

And not all the brewing reactions are done in the same organism…

• Starch is broken to sugar by the fruit or the grain

• Sugar is converted to pyruvate by the yeast

• Pyruvate is SOMETIMES converted to ethanol by the yeast

– Yeast won’t ferment if there is too much sugar or too little oxygen

What determines the type of wine?

• 1. Type of yeast: beer yeast, wine yeast, mead yeast, cider yeast, sake yeast, et al.

• 2. Sugar source: grains, fruits, vegetables, molasses, milk, etc.

• 3. Non-sugar flavors: hops, tannin, wood, acid blends, fruit flavors, spices, etc.

• 4. Quantity and time

A proposition about brews:

Only the type of yeast you use REALLY determines the type of brew you create.

The rest just alters the flavor. All brews made with wine yeast are types of wine, all made

with ale yeast are types of ale. Barley mixed with grapes and fermented with Belgian ale

yeast is a type of ale, not a type of wine. Honey fermented with Pasteur Red is a wine, not a true mead.

Yeast in brewing

• It is all the same species, Saccheromyces cerevesiae (brewer’s yeast)

• Some other yeasts are… – S. plombe (bread yeast)

– S. telluris

– Brettanymyces bruxellensis

– Cryptococcus neoformans

– Candida albicans et al.

– …and many thousands more.

What difference does yeast make?

Genetic variations make huge differences of flavor and require different conditions

Temperature

Growth speed

Sugar amount

Sugar type

Flavor compounds produced

Lager yeast

• Lager yeast has a dense protein coat, and is denser than water. It is also cryophilic.*

• Ferments at the

bottom of vessels

• Preferentially uses

maltose or simple

sugars

Maltose (a-1→4-glucopyranosyl-glucopyranose)

Sucrose (a-1→2-glucopyranosyl-fructofuranose)

Common in grain Common in fruit

Ale Yeast

• Ale yeast has less protein content in its cell wall, and hence is less dense than water. It is generally mesothermic.

• Ferments at the

top of vessels,

foamlike

• Like lager, it

preferentially

metabolizes maltose or simple

sugars

Beers in general

• Because of their preference for maltose, and their inability to ferment certain flavoring trisaccharides, lager and ale yeast are preferred for beer.

• Also display a range of ester synthase enzymes, yielding flavor overtones

– Propyl acetate (pear) and butyl acetate (apple)

– Ethyl butyrate (pineapple) can be activated, et al.

Wine Yeasts

• Most species of grape have yeast strains uniquely suited to them

• Example include Côte de blanc, Montrachet, Flor sherry, and Premier cuvee, among others

• Most tend to be slow growing

• Most tend to have higher alcohol tolerance

– Most wine yeasts tolerate 13% - 18%

– Most lager and ale yeasts tolerate 5%-12%

Wine Yeast

• Wine yeasts preferentially metabolize sucrose and simple sugars.

• They are slow at using

maltose or lactose

• Varieties exist that range from

cryophiles to mild thermophiles

• Have capacity to produce large

amounts of ester flavors

A few strains of wine yeast

• Pasteur Champagne: ferments dry (less residual sugar)

• Pasteur Red: ferments fruity (makes more esters)

• Bordeaux: ferments very dry and very fruity (extremely high alcohol tolerance)

• Cabernet Red: mild thermophile, high ester

• Assmanhausen Rot: slow growing cryophile

Sugars

• The sugar for fermentation comes from various plants or animals

• The fermentable sugar is liberated from starch

• Sugar is liberated as mono-, di-, or tri-saccharides

– Maltose and sucrose are disaccharides

Sugar sources

• Grains

– Barley

– Wheat

– Rice

– Corn

– Other grasses

Fruits

• Grapes

• Apples

• Berries

• Bananas

• And many more…

The sugar source will leave some flavor

…and the yeast enzymes make some flavor

• EC 3.1.1.67 - fatty-acyl-ethyl-ester synthase

– Esterizes ethanol

to various available

fatty acids

• Atf1p – acetyl transferase

– Esterizes acetate to

various primary alcohols…

…and the strain of yeast matters

• California Ale yeast WLP001 acetyl tranferase binds isoamyl alcohol better than butanol

– This causes it to have slightly more “banana” overtone than “apple”

• Irish Ale yeast WLP004 acetyl transferase binds butanol and propanol better

– It therefore has distinctive “apple” and “pear” overtones

“Blueberry Yeast” Blueberry flavor 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromen-4-one

There is a strain of yeast that produces this flavor.

There is another that produces menthol.

…and various additives give some flavor

The characteristics of your beverage

1. Sweetness: This will be caused by unfermented (or unfermentable) sugar. “Dry” wines have low sweetness.

2. Acidity: the pH is lowered by citric, malic, and tartaric acid

3. Tannin: polyphenol, which tastes dry, and which acts as a preservative

4. Fruitiness: the esters which have remained or been formed in the fermentation process

5. Body: the texture of the wine. Alcohol content is a large contributor to this.

The Goal

• A drink which has some balance to these characteristics!

Stages of brewing

1. Extracting the sugar: for beer this is called “mashing” and for wine it is called “pressing”.

2. Innoculation with yeast.

3. Primary fermentation: alcohol level is made at this point.

4. Secondary fermentation: esters and flavors develop at this point

5. Consuming. Best left to the masters.

Today’s Recipes

#1 Grape wine: a combination of table grapes, concord grapes, fox grapes, and muscadine grapes, with Pasteur Red yeast

- extra sugar is necessary when you use fox grapes

#2 Banana wine: just bananas! …with

champagne yeast. - we will need to add acid blend and

tannin, because bananas don’t come with those

Today’s Recipes

#3 Cranberry/crabapple/rosehip wine: because it’s just crazy enough that it might work. With cote-de-blanc yeast.

- This yeast grows slowly and works best with other fruits than grapes.

- Extra sugar will be needed, because crabapples impart apple flavor but no sugar

- Rosehips should make this wine somewhat spicy

Today’s Recipes

#4 Kolsch Ale: This is to show how extremely similar ale and winemaking are. Made with WhiteLabs WLP029 German Kolsch Yeast

– It will mature in two months rather than two years

– The hops blend gives the preservative, instead of the tannin.

– The barley will also add flavoring, as well as sugar.

In addition

• We will “rack” some previously made wines

– “racking” means “siphoning into a new fermentation vessel to separate from the dead yeast”

• We will “bottle” some previously made wines

– Bottling is the last stage of secondary fermentation. The wines must stay in the bottles until their flavor is finished developing.

Thank you!

• Dmitry Liskin, for introducing me to the craft and encouraging me.

• The American Chemical Society, for sponsoring this event.

…and especially

• Dr. Sumie Shima, for tolerating my midlife eccentricities.