Wine Blogging Wednesday 59: Osake desu!

Konnichi-wa, readers. Let’s take a break from the strawberry story for another edition of Wine Blogging Wednesday, this time a staggering 8 days late. Having taken five weeks of Japanese classes back in 1999, I was excited about this month’s WBW. Richard, Boston’s Passionate Foodie and unrepentant sake enthusiast, chose the theme of homage to Kushi no Kami (the god of sake. By the way, kami in Japanese relates to gods or divinity, as in kamikaze: “divine wind”). So I chose two different styles of sake to compare, having only a small amount of experience with the drink. I picked them up at the local liquor store (the one closest to Cornell), and taking a look at the shelf, I get the feeling that these sakes are pretty high production, Gekkeikan being the Godzilla of American sake distribution.

Please observe the members of this kikishu or sake tasting.

Before we start, some sake vocabulary:
Junmai: Some sakes have alcohol added near the end of fermentation. Only rice, yeast, koji (more on that later), and water are allowed in sake that is classified as junmai. Junmai is like the Rheinheitsgebot of Japan.
Honjozo/Ginjo/Daiginjo: these have to do with the amount of milling the rice goes through before fermentation. You can think of rice as a hard protein/gluten shell with a starchy center. The more milling, the more starch is available for fermentation, and (according to many) the higher quality the sake. In order, the rice grains of the aforementioned are milled to 70%, 60%, and 50% of their original size.
Genshu: Cask-strength sake. Sake finishes fermentation around 18-20% alcohol. Most is diluted with water, but genshu is the real stuff, straight out of fermentation.
Nigori: unfiltered sake. I guess unfiltered is misleading, since there aren’t actual chunks of rice in the drink, but only coarse filtration is applied after fermentation, resulting in a milky, cloudy beverage with lots of sediment floating around.
SMV: Sake Meter Value. Ranging from -15 (really sweet) to +15 (dryyyy), this indicator appears on most bottles.

For more sake terms, and there are many more, you can refer to this website, the sake glossary.

(NB: I follow the New York Times style for grape varieties [i.e., riesling is not capitalized], so I will go with the NYT here and not put an accent on the word “sake”. Japanese is a context-centered language, so use your context clues.)

Horin Gekkeikan Sake (Ultra premium) Junmai Daiginjo

The first contender

ABV: 15.5%
SMV: +2 (on the dry side)
Milling: 50%
Price Point: $13, 300 mL bottle
Looks: Pours clear with an ever so slight yellow tinge
Nose: black licorice and melon. I get the alcohol after a while. Bit of a brewery smell coming on.
Palate: Alcohol pronounced but nice, not a very complex matrix. Somewhat creamy mouthfeel, yeasty/bready, very clean and crisp. I’d like some more acidity, personally.

I have had many sakes that smell like melon. I mean the unripest part of a honeydew. I wonder what’s up with that. Studies suggest that phenylethanol shows up in both melons and sake, but to me, phenylethanol smells like rose/honey (most like Dundee’s Honey Brown beer, actually, if you’ve had it). (Hayata et al., Analysis of Aromatic Volatile Compounds in ‘Miyabi’ Melon (Cucumis melo L.) using the Porapak Q Column., J. Japan. Soc. Hort. Sci., 2002) I suspect there is not as much research on sake aroma compounds as wine aroma compounds. Perhaps we’ll tackle this in a later entry. After a few days in an open bottle (I actually tasted these last Thursday and am just now revisiting them…) the licorice is overwhelming.

Momokawa Pearl Junmai Ginjo Nigori Genshu Sake

Pearl, one of a series of sakes who share names with Pokémon games (Silver, Ruby, Diamond, Pearl)

ABV: 18.5%
SMV: -12 (pretty sweet)
Milling: 60%
Price Point: $14, 750 mL
Looks: cloudy white and opaque with slight yellow, like buttermilk
Nose: big, banana, coconut, piña colada
Palate: love the texture that the sediment gives, long finish

I had a small sake tasting with friends a few months ago and the nigori was definitely my favorite. The same applies here. I am a very big fan of this beverage. A++ would buy again!! If you buy nigori, make sure to shake it before you pour, as the sediment will separate in the bottle.

Overall, most of the sake you’ll find in the liquor store will be cheap (I don’t think I’ve seen anything over $25), light, and very flavorful. I’m just getting into it, but I really do like it, especially nigori-style. Perhaps next time I will ask for a sake flight with some raw fish at Ithaca’s local sushi haunt, called, aptly, Sushi Osake.

Science!

Koji mold growing on steamed rice. Image from Sakayanyc.com

Sake seems as diverse a field as wine, so it’s tough to sum up sake in one Science! segment. As a biology guy, the most interesting part of sake-making for me is the addition of koji to the rice. Koji is better known to the scientific world as Aspergillus oryzae. It is a mold added to rice before fermentation to break down the starch into fermentable sugars for yeast. Just as beer brewing requires barley to be malted (where enzymes in the barley [amylases] break down the starch in the grain), sake brewing requires koji. It’s possible that koji also contains enzymes that contribute to the final flavor and aroma of the finished fermented product. For example, glutaminase converts glutamine to glutamate, the primary component of umami taste (Kitamoto, , “The Molecular Biology of Koji Molds”, in Advances in Applied Microbiology,Vol. 51, ed. Laskin et al., Academic Press, 1997) Interestingly, koji is also used to ferment soy sauce and miso.

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Strawblog: Day 2: Chaptalization, or the boring math part.

When we last left our berries they were cold-soaking overnight in the fridge after crush and pectinase treatment.

Hydrometer, zoomed-in

The next day it was time to take some measurements. I squeezed the pulp in a hop bag to get straight juice out into a graduated cylinder. I suppose you don’t need a graduated cylinder but the amount you measure has to be deep enough to fit a hydrometer. The hydrometer, pictured right, correlates density of the mixture to height, which is related to the amount of stuff dissolved in there. The density can be converted to Brix (named after Herr Brix, reputed to have invented the hydrometer and the formula which converts specific gravity (i.e., density) to percent sugar), which is a measure of soluble solids per 100g of solution, or more simply, percent sugar. A reading of 20 degrees Brix corresponds to 20 grams of dissolved solids per 100 g of solution.

(NB: Brix is not necessarily a measurement of sugar, however, in a given {must}, 90-95% of dissolved solids are fermentable sugars. Others include non-fermentable sugars like arabinose and xylose, organic acids, polyphenols, etc. )

Hydrometry on the juice, with graduated cylinder for extra science-y goodness.

The strawberries came in at 7 Brix, which is 70g/kg and the must is about 2.88 kg (estimated from the density), so we’ve got about 202 g of sugar. If I were to ferment this as is, I’d have the alcoholic equivalent of strawberry light beer. We’re making wine here, not Arbor Mist. Let’s up the ante a little, shall we? More sugar means more alcohol.

Let’s say I want to chaptalize (i.e., add sugar to the must, named after Monsieur Chaptal, who discovered the relationship between sugar and alcohol in wine) up to 20 Brix. How much do I have to add? ALGEBRA!

202 + x (g sugar)
——————— = 0.2 (g/g); x= 467.5 g sugar
2880 + x (g total)

Unlike Alton Brown, I don’t have a scale in the kitchen, so I have to work with volume. According to sugartech.com , the density of bagged white sugar (sucrose) in 700g/L = 165 g/cup. So to get up to 20 we need 2 5/6 cups. Let’s make it an even 3.

From strawberry juice to strawberry syrup. I think I underestimated the volume.

I added 3 cups sugar. If this were Beaujolais, I’d be locked up. Just as a check, I took the Brix measurement again. Whoops, the final Brix was 26! I guess I underestimated my volume of must. Apparently I did, because when I filled up the growlers I had about 3 quarts instead of the gallon that I thought I had. I didn’t want too much headspace on the wine so I topped them up with some cherry juice (no preservatives…) I had on hand. After this addition, the final Brix reading was 23. Depending on what formula you use (and the yeast), that should lead to an ABV of 12-13%.

Science!
During fermentation, sugars such as glucose and fructose are converted into carbon dioxide and ethanol in the following reaction:
C₆H₁₂O₆ –> 2 C₂H₅OH + 2 CO₂
This means the theoretical yield for ethanol on a per mass basis is about 0.51 * sugar, or ~62% on a “by volume” basis. This doesn’t really happen and often the Brix to ABV conversion is more like 0.55. Why? Some of that sugar goes into yeast biomass, some of it becomes glycerol, and some alcohol is carried away by CO₂… More on CO₂ next time, when we prepare to start fermentation…

PS I know what you’re thinking… I added sucrose, which is C₁₂H₂₂O₁₁ ! That doesn’t fit into the formula! Luckily for me, yeast produce an enzyme known as invertase, which converts sucrose into its constituent monosaccharides, fructose and glucose, both of which are C₆H₁₂O₆ and both of which are easily consumible by yeast. It’s also what they add to chocolate-covered cherry cordials to make them all gooey on the inside. (The invertase breaks down the sucrose-saturated fondant into fructose and glucose.)

Bonus question: If I had 3 quarts of 26 Brix juice and added 1 quart of cherry juice to bring it to 23 Brix, what was the Brix of the cherry juice?

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

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)

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….