Strawblog: Day 1

Sarah and I are members of the Sweet Land Farm CSA (community-supported agrictulture) in Trumansburg. For those unfamiliar with the CSA concept, you basically invest in a share of the farm and your dividends are vegetables and fruits. Anyway, one of the benefits of membership is unlimited U-Pick strawberries. Naturally, I picked about 5 quarts of berries and decided to make them into wine. It then occurred to me that I could document my winemaking process and drop some winemaking knowledge bombs along the way. So, here goes.

(NB: Strawberries aren’t technically berries, they’re “accessory fruit“, since the edible part is not generated from the ovary of the plant, but surrounding tissue. Grapes, however, are berries.)

Harvest: I tried to pick fruit that wasn’t at all mooshy or damaged by mold, since molds often produce enzymes that do unsavory things to wine. For example, {botrytis} produces a lot of the enzyme laccase, which oxidizes polyphenols in fruit juice to make browning products, and unlike other polyphenol oxidases, is resistant to inhibition by sulfites. (Dewey et al., “Quantification of Botrytis and laccase in winegrapes”, AJEV, 2008). Avoiding soft fruit was difficult since it has rained here on and off for about the past two weeks. Also, strawberry plants are low to the ground and the leaves hold water like bowls, so it’s a pretty wet environment.

The destemmed fruit

The destemmed fruit

Destemming: I manually destemmed all the berries, so as not to have stemmy, vegetal aromas like methoxypyrazines (bell pepper, peas) around.

Crush: This was the fun part. I crushed the berries with my (clean) hands, squishing them between my fingers. The hearts of the fruit are kind of hard, so eventually I switched over to a potato masher. What I ended up with was basically strawberry stew, with solid matter still pretty much outnumbering the straight-up juice. To rectify this, I added an enzyme called pectinase.

Pectin is a polymer of sugars, kind of like starch (amylose)

Pectin is a polymer of sugars, kind of like starch (amylose)

Enzyme treatment: Pectinase You’re probably familiar with pectin. It’s the powder you add to pretty much any cooked fruit to take it from fruit slop to jelly or jam. Pectin is a polysaccharide (bunch of sugar molecules bonded together) that is found in the cell walls of plants. Apples and citrus fruits have a lot of pectin, but grapes and strawberries also have some. Pectinase, a standard winemaking treatment to aid in {must} clarification, chops up the polymer into its constituent sugars, thinning out the liquid and aiding in separation.

Cold Soak: I actually neglected to pick up some yeast before I got started, so I decided to put the {must} in the refrigerator overnight. The purpose of this was two-fold. One, I didn’t want it to start fermenting with the natural yeasts (including undesirables like Kloeckera). Second, cold-soaking whole or crushed grapes has been shown to aid in extraction of anthocyanins (color compounds), adding some color to some wines (Gómez-Miguez et al., “Evolution of colour and anthocyanin composition of Syrah wines elaborated with pre-fermentative cold maceration”, Journal of Food Engineering, 2004), though the jury is still out on its effectiveness. It’s become clear to me that I am going to treat this like a red wine.

Up next: Starting fermentation….

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Published in: on 3 July 2009 at 7:39 am  Comments (2)  
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2 CommentsLeave a comment

  1. Can’t wait to taste the “fruits” of this labor.

    Wish I had taken your Twitter advice and used our last batch of berries for a similar project!

  2. [...] weakening the cellular structure of the skins to promote the release of color compounds. I sort of did this with my strawberry wine, but only because I forgot to buy yeast that day. You’ve got to be careful with extended [...]


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