Strawblog: Day 2 continued: Fermentation prep

So once I had the must chaptalized, it was (finally) time for some fermentation.

Forget Listerine, Devil's Springs is 160 proof, enough to sterilize pretty much anything.  Also, don't take a sip by accident.  Your face might melt right off.

Forget Listerine, Devil's Springs is 160 proof, enough to sterilize pretty much anything. Also, don't take a sip by accident. Your face might melt right off.

Before starting fermentation, I wanted to make sure that my fermentation was clean, and that means sterilizing. Most wineries would sterilize using steam or detergents and sanitizing agents. While these are available for homebrewers (B-Brite and C-Brite are common sanitizers), I chose a different method of sterilization. I usually use Devil’s Springs double strength vodka to make boilo, a family recipe for a hot beverage served around the holidays (I’ll probably post a recipe around that time), but in this case it has another use. It’s 80% alcohol (ethanol), which is slightly above the 70% ethanol we use in lab to sterlilze ad disinfect our benchtops. I put some of this into all the bottles, hoses, growlers, and airlocks I plan to use for fermentation. Usually before I add anything to the must (hydrometer, for example), it gets treatment with regular vodka. Ask any commercial winemaker and they will tell you that about 90% of their job is keeping things clean and sterile.

When I picked the fruit it had been raining for two weeks beforehand, leading to a lot of damaged and mushy fruit (i.e., growth of fungus). I also wanted to curb the growth of any bacteria or other microorganisms which would like to feast on my sugary must. So I added some sulfur dioxide. Sulfur dioxide is an antimicrobial and antioxidant agent. The various forms of SO2 are known as sulfites, and have been used in winemaking for thousands of years. Molecular SO2 is the actual antimicrobial agent and its concentration as free molecular SO2 depends on pH and several other factors. I can’t really measure the pH of my must at the moment so I took a suggestion from the Handbook of Enology (Ribereau-Gayon et al.), a famous winemaking textbook by many of the premier enologists in Bordeaux, and added about 40 ppm SO2 to the must (1/2 tsp of some of the 50 g/L SO2 that I swiped from my winemaking class. Don’t tell Ramón.)

I also added some tannin for color stabilization. Strawberries don’t contain that much tannin, and tannin helps to stabilize color in the long term by binding to color compounds called anthocyanins. In the long-term, co-pigmentation of tannins and anthocyanins stabilizes and contributes to color. Will the 1/2 tsp of {tannin} contribute? Probably not, since this wine probably won’t be around long enough for many co-pigmentation reactions to occur. It’s worth a shot, though, and the tannin may contribute some {astringency}, which I fear untreated wine may lack. The must certainly isn’t too astringent.

Another addition I made was Fermax, a yeast nutrient containing diammonium phosphate, which provides nitrogen to the fermentation. Nitrogen is an essential component to a fermentation because yeast need it to make amino acids, which are the building blocks of the proteins and enzymes the yeast need to manufacture in order to grow.

L513

The last task was to get the yeast ready for their delicious meal. I got out my packet of Lalvin EC-1118 yeast (enough for 5 gallons) and sprinkled out a small portion of the packet. EC 1118 is a yeast isolated from the Champagne region* and for various reasons is the yeast of choice for ciders and fruit wines, as well as for sparklers. The yeast comes dehydrated and needs about 15 minutes in luke-warm water to rehydrate and reanimate. To make it as nice as possible for the yeast, I also warmed up the must by floating the mixing bowl I was storing everything in in warm water while the yeast were rehydrating. After 15 minutes, the yeast went into the strawberry must. I poured the mix into two growlers and attached the airlocks (filled with rum). Let the fermentation begin!

IMG_1525

By the way, I obtained most of my supplies for this endeavor (yeast, Fermax, pectinase, sorbate, tannin, hydrometer) from the Ithaca Beer Company, which has many resources for home winemaking and brewing, includiny carboys, malt, recipes, hops, and lots of other accessories.

Science!
In most cases, the yeast used to ferment grape juice into wine is Saccharomyces cerevisiae. EC1118 is actually a strain of Saccharomyces bayanus, a very closely related yeast. S. bayanus and its cousin S. pastorianus are often used in brewing. In reality, though, S. cerevisiae, bayanus, and pastorianus are so closely related that their taxonomies have varied. At first, bayanus was believed to be a subspecies of cerevisiae. Nowadays, they are largely considered a species complex, and the difference between them seems largely academic. (Raineri et al., “Saccharomyces sensu stricto: Systematics, Genetic Diversity and Evolution”, Journal of Bioscience and Bioengineering, 2003)

Published in: on 1 August 2009 at 5:27 pm  Comments (1)  
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One CommentLeave a comment

  1. Wow!


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