When I woke up the next morning, though, I discovered that my explosion-prevention strategy had a slight flaw.

I woke up to this:

Strawberries. Everywhere.

Turns out some strawberry pulp had made its way up the necks of the growlers and lodged itself into the airlock, producing a plug of strawberry slop. Eventually, the pressure built up inside and popped the stoppers, sending sweet, sticky strawberry pulp everywhere within about a 5-foot radius of my fermentation area (read: the kitchen counter). It almost hit the ceiling, as did Sarah when we woke up at 7 am to find strawberry slurry everywhere. The cap from one of the airlocks was later found on the other side of my apartment.

It turned out that I didn’t lose too much juice, so I cleaned everything up the best I could (luckily the walls and cabinets are white, so a little bleach worked nicely) and set the airlocks back in to continue fermentation, which, not surprisingly, was proceeding vigorously. Check out the bubblage in the video (you may have to tilt your head 90 degrees left to get the full effect). I sound a bit stoned, but I’m really just in awe of science.

[youtube=http://www.youtube.com/watch?v=ki7jS4w8J9w]

By the way, fermentation comes from the Latin fervere, meaning “to boil”. Looking at a fermentation in progress, it’s not surprising that the Romans would think that’s what was going on. And I guess that technically, CO2 is escaping the surface tension of the liquid, so I guess in a way it is boiling… but I digress.

Science!
When Jean-Claude Antoine Chaptal discovered the relationship between sugar and CO2 in a fermentation, he solved a very big problem in Champagne. Knowing the exact amount of sugar to add to a secondary fermentation saved many, many bottles from exploding. So how much CO2 is generated from the sugar in a fermenation? Remember high school chemistry? No? Well buckle up because you’re going back to Mr. Burcik’s class.

OK, remember our master chemical reaction of fermentation?

sugar (C₆H₁₂O₆) –> 2 CO₂ + 2 alcohol (C₂H₅OH)

That means for every molecule of sugar turned into alcohol, 2 molecules of CO2 form and escape from the liquid in the form of carbon dioxide gas. Let’s say that I had been really dumb and sealed the vessels completely instead of allowing for the CO2 to bubble out. Also, for simplicity, let’s neglect the CO2 dissolving in the wine in the container (that gets complicated), and assume that CO2 is an ideal gas (not a great assumption but we’re not teaching thermodynamics here…yet). Some of these values are what we engineers call “engineering estimates”.

***Warning: Chemistry and Math ahead. If you just want to know if the thing will explode or not, skip to the bottom***

Anyway, our must is at 23 Brix, which means that in one growler, there is about 345 g of sugar (1.5 kg of must).

345 g sugar is 1.9 moles (glucose is 180 g/mol), so we will produce 3.8 moles of CO2 in the growler. Not so bad right?

Remember the ideal gas law? At standard temperature and pressure, 1 mole of gas takes up 22.4 L of space. Well, inside this vessel, the pressure will be anything but standard, and the temperature is 25C, not 0C. A little PV = nRT and we find that this gas wants to take up about 96 L when it is confined to about 2 L of growler. That means the pressure in there will go up to about 48 atmospheres. That’s about 20 times more pressure than in car tires.

If the container were at 48 atm and suddenly failed, the energy contained in the resulting adiabatic explosion would be V*ΔP = 2 L * (48 atm – 1 atm [atmospheric pressure]) = 9.5 kJ, which is the equivalent of 2.2 grams of TNT. That may not sound like much, but after searching some sites that in retrospect are only quasi-legal, I found out what 2 grams of flash powder (more or less equivalent to TNT in explosive energy, Vermeij et al., “Morphology and composition of pyrotechnic residues formed at different levels of confinement”, Forensic Science International, 2009) can do.

[youtube=http://www.youtube.com/watch?v=iVF8SdSR4mo]

(Note: I am not dumb enough to have actually done this. There are lots of explosion videos on YouTube, though, and it’s not really that suprising.)

The bottom line is be careful with fermentations! I’m not saying don’t try this at home, (in fact, I hope I’m encouraging it!) but don’t seal off your fermentation, whatever you do! The growler would probably have broken around 4-5 atm anyway, so I wouldn’t have to worry about an M-80 (~2.5 g TNT equivalent) going off in the kitchen. In either case, though, I’d have a much bigger mess.

Extra credit: Using the above calculations, how much pressure does a fermenting champagne bottle get up to? Hint: secondary fermentations in 750 mL bottles are usually dosed with about 20 g of sugar.

                          

A cool spring afternoon with some bubbly. Click to visit the Dr. Frank website

Appelation: Finger Lakes Champagne (now, before you get all grumpy, let me assure you that this sparkling wine is legally allowed to be called “champagne” in the U.S., see this article for more details.)
Varietal: Pinot Noir 95% Pinot Meunier 5%
ABV: 11.1% (marked 12% on the bottle, but this data is from winemaker’s notes on the Dr. Frank website)
RS: 1%
Price Point: $30
Notes:
Looks: Faint yellow with lots of bubbles
Nose: Subtle fruit around. Later it gets mushroomy, earthy. What I thought of was our middle school pool. Not necessarily the chlorine smell, but the mix of locker room and warm humidity. Don’t misinterpret that, it’s a good thing, because swimming for gym class was the best gym class.
Palate: Wow. Rich {mouthfeel}, very full-bodied. A little bit of yeasty, bready aroma sneaking in on the palate. Acidity balances this wine nicely, and the touch of residual sugar smooths everything out. Very balanced, full-bodied, and complex. I really, really like this wine.
Rating: 4 corks

Lots of bottles. The crude cell phone pic does not really capture the sheer number of bottles. Click to enlarge

Keuka Lake makes its debut on Ithacork and comes out swinging! Dr. Konstantin Frank Vinifera Wine Cellars has become one of the most well-known wine producers in the Finger Lakes. This is likely due in part to the fact that they were the first to successfully make wine with {vinifera} grapes in the region. Also, they are darn good at it. In fact, when I arrived in Ithaca, one of the first names I heard in reference to wine in the Finger Lakes was Dr. Frank. I had the opportunity to tour the winery as part of a winemaking class at Cornell. On the tour, we were afforded a rare opportunity to see the cellars of Chateau Frank, the sparkling wine production house. A lovely elderly (but quite spry) woman, the wife of the late Willy Frank (Dr. Konstantin’s son) gave us the cellar tour and we were able to see bottles and bottles and bottles of sparkling wine at various stages of the famous Champagne process. You can read about it in the wikipedia link, but briefly, base wine is bottled with a dose of sugar and yeast and a secondary fermentation occurs in the bottle. The bottles are left on the yeast for a long time, usually on the order of years before the yeast is disgorged and the champagne is bottled. It was awesome. If you like this wine, or you like your bubbly a little sweeter, may I suggest the Célèbre crémant, made with riesling grapes! It is also fantastic.

This wine is a great example of sparkling wine in the Finger Lakes. To make sparkling wine, winemakers usually start with base wines that are high in acid and relatively low in sugar, something that cool climates can produce without even trying. Even though sparkling wine is labor- and equipment-intensive, many of the sparkling wines I have had from the Finger Lakes (Lamoreaux Landing is another good bet) have been excellent. I think that sparkling wine has the potential to be huge in this region. One last note: to many people, sparkling wine is something only drunk on special occasions, celebrations, or hungover mornings with orange juice. I had this wine with a sub from Wegman’s, and I’ve previously been known to pair sparkling wine with Southern fried chicken. There is lots of great sparkling wine out there, and sometimes opening a bottle is cause enough to celebrate!

*Science!
Some of the rich mouthfeel that shows up in sparkling wines can be attributed to extended contact (aka tirage) with yeast lees (i.e., yeast cells). Over time, yeast cells will die and undergo cell lysis, or autolysis. Products of yeast autolysis include mannoproteins, which have been shown to increase perceived body and mouthfeel in wines (Ref: Alexandre and Guilloux-Benatier, “Yeast autolysis in sparkling wine – a review”, Australian Journal of Grape and Wine Research, 2006). Basically, long periods of aging (in this case several years) will cause the dead yeast cells to break up, releasing nucleotides, enzymes, cell wall bits, and other insides into the wine. How long to age the wine on the lees and when to bottle is a winemaking decision, and according to winemaker Paul Brock (Lamoreaux), sparkling wine that is on the shelf is generally ready to drink, as all the aging has been done in the cellar.

                          

Sheldrake is one of my favorite wine producers on Cayuga Lake. They almost exclusively grow {vinifera} grapes and most of their wines are very good quality. Plus, they have a nice view of the lake, a nice tasting room, their staff are really knowledgeable. In fact, they keep a binder behind the counter with all of the winemaker’s notes on every wine that they have available to taste, including pH, total acidity, fermentation notes, types of oak used, and much more. Great for a wine geek like myself.

This particular chardonnay is fermented in all stainless steel with NO {malolactic fermentation} and never sees any oak, which allows the straight up aromas of the wine to shine. Don’t get me wrong, I like a big, oaky, buttery chardonnay, but I would rarely call it “refreshing” or “lively”.

Science!

Oenococcus oeni converts malic acid into lactic acid, "softening" a wine.

I guess this is as good a time as any to talk about malolactic fermentation. Malolactic bacteria, such as Oenococcus oeni (guess where it was first discovered) convert malic acid into lactic acid. What does that have to do with wine? The primary organic acids in wine are tartaric acid and malic acid. You may be familiar with malic acid, as it is the main acid in apples. Lactic acid is the main acid in yogurt. In fact, the Germans call malic acid Äpfelsäure and lactic acid Milchsäure (tartaric? Weinsäure, of course!). But we digress.

Warheads. Ridiculously sour.

Malic acid has two acidic protons (i.e., two hydrogen ions that like to leave the molecule). Lactic acid only has one acidic proton. Thus, for the same concentration of malic and lactic acid, malic will be perceived as harsher and more acidic. I have done this test with several different acids and it is not fun. In fact, remember Warheads candy? The candy with the super sour coating? Well, the coating is primarily malic acid. Wow, my mouth literally watered when I typed that as I was brought back to fifth-grade Warheads eating contests.

The point is that malolactic bacteria are often inoculated into wines after the primary alcoholic fermentation (yeast) to reduce the overall acidity of the wine.  Reducing acidity is not the only benefit of MLF, though.  It can help reduce {acetaldehyde} and release “trapped” aroma compounds enzymatically (Ref: Grimaldi et al., “Identification and Partial Characterization of Glycosidic Activities of Commercial Strains of the Lactic Acid Bacterium, Oenococcus oeni”, AJEV, 2000). A majority of reds undergo malolactic fermentation. Only some whites do, mostly chardonnay. The best way to determine whether or not your wine has undergone MLF is to try to detect a buttery aroma, like movie theater popcorn. This is the aroma compound diacetyl, produced by ML bacteria, which merits its own separate discussion.

                          

Left to right: 2007, 2002, 2004 December Harvest, 2004 January Harvest

From youngest to oldest:

Sleek, stylish bottle on the 2007

Sheldrake Point 2007 Riesling Ice Wine
Varietal: Riesling
ABV: 12.6%
Residual Sugar: 16.5% (165 g/L)
Appelation: Finger Lakes
Price point: $65 for 375 mL (half-bottle)
The 2007 looks pretty much like any normal riesling would, pale yellow in color, though noticeably thicker in the glass on swirling. It also smells like a Finger Lakes riesling, with characteristic light floral and citrus notes. Also, it’s got a little stonefruit (I wrote “peach”) and pineapple thrown in there. On the palate, lively acidity stands up to the considerable sweetness very well, for a very fresh, zingy feeling. Lemon and lime join the party on the palate, kind of like Sprite. (Interestingly, all of these wines have quite a bit more sugar than Sprite [~110 g/L]). Really great, and not just for dessert. This {well-balanced} wine plays nicely with blue cheese and walnuts, and would likely compliment spicy foods (e.g., Thai or Indian) pretty well.
Rating: 3.5 corks

Sheldrake Point 2004 December Harvest Riesling Ice Wine
Varietal: Riesling
ABV: 12.8%
Residual Sugar:15.5%
Appelation: Finger Lakes
Price point: $90 for 375 mL
This wine was bit more golden in color. Muted fruit aromas compared to the 2007 give way to more honeyed character in this one. I imagine the honey character also comes psychologically as a result of the increased viscosity of the wine. It’s also got a long finish.
Rating: 2.5 corks

Sheldrake Point 2004 January Harvest Riesling Ice Wine
Varietal: Riesling (grapes from 2003 season harvested in January 2004)
ABV: 12.2%
Residual Sugar: 19.5%
Appelation: Finger Lakes
Price point: $100 for 375 mL
The apparent crown jewel of the tasting, this wine was served at a Governor’s Ball at the White House in 2006.

Kerosene? In my Riesling? It's more likely than you think.

The label says 2004 but the grapes were from the 2003 vintage and harvested in January 2004, so for all intents and purposes, this is a 2003.  It’s starting to show its age. It’s just beginning to develop the aroma of “petrol” (a nice way of saying “kerosene”).*  This aroma is common in older rieslings and found especially in German rieslings (probably because many German rieslings will not be released for years after bottling, while FL wines usually come out ASAP.)  I have to say that the petrol is not a bad thing in this wine, and in fact it adds an interesting layer of complexity. I also noted some citrus peel in addition to peach aromas.
Rating: 2.5 corks

Sheldrake Point 2002 Riesling Ice Wine
Varietal: Riesling
ABV: 11.5%
Residual Sugar: 20%
Appelation: Finger Lakes
Price point: $70 for 375 mL
The oldest and darkest of the bunch, with its deep gold color, is on the verge of browning. I noticed two things right away on the nose. First, a whole lot more of the petrol character than the 2003. Secondly, and unfortunately, this wine is a bit {oxidized}. In all fairness, it’s possible that I got a bad bottle. However, I actually got a re-pour (for an errant fuzz in the glass), and the wine remained the same. If the whole lot of wine tastes like this, they really shouldn’t be selling it for $70, or maybe even at all.
Rating: 1 cork

Overall, I enjoyed the tasting. The wines were served to small groups (in this case, me and 5 friends) so it was like a private tasting. The host was informative but a bit blabby. At a certain point I just wanted some quiet so I could taste the wine. Others, though, got a lot out of it. I still find ice wine in general a bit pricey for me. And though they went out of their way to pair with some non-dessert foods, I’m not sure I would crack a $65 half bottle to down with dinner. For me, I’ll leave it as an appetizer or dessert, both of which it’s perfectly suited for.

*Science!
Ice wine is usually made by leaving the grapes on the vine until winter.  When cold temperatures come around (~15-18 F, according to the tasting room manager), the frozen grapes (the ones that haven’t {rotted} or been eaten by deer or just fallen off the vine) are picked and immediately pressed. Out in the cold, most of the water inside the grapes will freeze, but a more concentrated solution of sugars and acids will not, producing {must} with very high sugar and high acidity.  The resulting juice is fermented (though usually not without difficulty), leaving a wine with a normal amount of alcohol for a wine (~12% abv) and high residual sugar. The labor-intensive process justifies the high price, as it is a pain in the butt to pick in sub-freezing temperatures, crush solid grapes, and ferment juice that is so high in sugar that yeast have a hard time surviving due to osmotic stress (Ref: Erasmus et al., “Genome-wide expression analyses: Metabolic adaptation of Saccharomyces cerevisiae to high sugar stress”, FEMS Yeast Res., 2003.)