Wine Diamonds: The Untold Story

Brad Post:

The adage goes something like this "diamonds are a girls best friend" but what about wine diamonds?  Perhaps you've encountered crystalline structures attached to the underside of your cork or maybe noticed sediment in the bottom of your wine glass and wondered what was wrong with your wine.

Are Wine Diamonds the new best friend of girls or are they indicative of bad wine?

Some background. Wine contains three primary acids: Tartaric (most abundant), Malic, and Citric (least abundant) and are responsible for the sour taste in wines.  There are preferred ranges of total acidity (TA) for white wines (6-9 g/L) and red wines (5-7g/L) - (notice white wines acidity is higher).

In the Midwest, the cold-hardy varietals that we are able to grow, and make into good wine, tend to push the envelope of high acidity. (The Frontenac grapes from this year were picked at 21 Brix and 16 g/L TA - crazy-high!). Reason for high-acid?  Either the grapes were harvested before they are fully ripened or may just be an artifact of the varietal being grown.

Back to the questions:  Are wine diamonds the new best friend of girls or are they indicative of a fault?  No.  No, is the answer to both questions.  Although interesting to look at and harmless to consume, wine diamonds are simply Potassium Bitartrate salts (or Tartaric Acid crystals) more commonly known by their kitchen cupboard name - cream-de-tartar. These crystals are soluble in juice but less so in wine. And this means that the acids in the juice are invisible (much like sugar dissolved in Kool-Aid) but in wine they can begin to crystallize and precipitate (fall out of solution) and ultimately collect on the cork or inside at the bottom of your bottle of wine.

In my next blog, I'll explain how winemakers try to minimize the chance of crystal formation and explain what I do around the winery to aid in the stabilization of wine.

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Brad Johnson is a contributing writer for Make Mine Wine Magazine, an artisan winemaker, researcher, teacher, and proud member of the Eastern Iowa Wine Club. He Tweets as "Iowine".

Winemaker Notes

Brad Post:

While most people were enjoying their Labor Day weekend at the beach or picnicking with friends, many of my fellow Iowa winemakers were busy picking wine grapes and processing them.

I thought it might be interesting to share some of my winemaker notes with you. These particular notes represent my efforts to craft a medium-bodied, Marechal Foch red table wine.

~Brad

Grower: Tom and Vicki Capper (Old Mans Creek Vineyard)
Quantity: Purchased 156lbs.
Quality of Grapes: After two weeks of heavy rain (3-11 inches) the berries we picked were in remarkably good shape. Although there were some indications of rot in some berries (we left those) but some probably got into our bins. The berries were mostly sound, few greenies, and few light red berries, but overall the berries were very good. We harvested on the Sunday of Labor Day weekend (9-6-09).

Marechal Foch Table Wine
Background: We wanted a medium bodied, low-herbaceous Foch wine, so we wanted to press early.
Brix: 21.2 (potential alcohol: 11.7%)
pH: 3.41
SO2 Addition: 1.5 grams (30ppm, sound quality grapes).
Pressed: 9-8 (t=36 hours)
Yeast: Inoculated at t=18hours (9-7) in morning (8 gram yeast).
Go Ferm: added with yeast (10 gram).
Quantity of must before pressing: ~11 gallons. (note: I didn’t press as hard as I could).
Quantity of juice after pressing: ~5.5 gallons

Notes: We had spontaneous fermentation on the morning of 9-7 and promptly inoculated must with cultured yeast. We also added 4 grams of VRSupra Tannin (2x more than I was supposed to – doh!).

9/7/09: Inoculated with yeast
9/8/09: Pressed must; very dark juice
9/9/09: Hydrometer: Brix = 13.5; added 4 grams of Fermaid K
9/10/09: Fermentation going very well
9/11/09: Fermentation slowing down and nearing completion; tastes and smells good.
9/13/09: Added: Lactic Acid Bacteria (LAB) - rehydrated with Acti-ML (nutrient). FYI: The LAB will convert the sharp tasting Malic acid in the wine to the more smooth Lactic acid. *Note: need to be careful about oxygen ingress from here forward as alcohol fermentation is nearly complete.

Bench Trials

Brad Post:

As an aspiring winemaker, few things get me as techno-wine-geeked-out as conducting bench trials. Now don't get me wrong, I love the notion of winemaking as a craft, an artistic venture of guiding a grape to its true greatness with love and care. But, there is the scientifically-minded Brad whose grape-juices get flowing at the thought of checking pH, TA, SO2 and conducting bench trials.

Bench trials allow a winemaker to tweak the wine, generally using sound scientific procedures and organoleptic analysis (taste and smell), to adjust via additions (e.g., sugar, acid, tannins, etc.) the final wine we all enjoy. For the home winemaker a bench trial is usually done by taste (on the fly), such as adding sugar to a finished wine to balance or sweeten it up before bottling.

For a commercial winery, whose livelihood depends on not screwing up, bench trials are frequently used prior to any additions. As an example, I volunteer at a local winery who is considering making a tannin addition to three of their red wines (several hundred gallons each). In advance of making an addition, the winemaker sought out three different tannin options (yes, there are several different tannins one can put into a wine...to add some mid-palate complexity) and set-up a strategy to assess the additions. Here is how it went:

We created a 3x3x3 bench trial matrix. This means, we have three types of tannins, at three different concentrations (e.g., 10g/hl - the low point; 20 g/hl - a mid-point, and 40 g/hl - a high point), and three different red wines. All told we are testing 27 bottles + 3 (standards = a comparison of the unaltered original wine) = 30 bottles of wine to taste.

After a set amount of time to allow the tannins to incorporate into the wine, the winemaker will bring together a group of volunteer tasters to evaluate which additions work the best for each wine. If none of the additions improved the wine quality then the standard (original) wine will be bottled.

I have to admit the bench trial process is enjoyable! Frankly, the critical evaluation of the wines (the tasting) is a lot of fun and in the end helps craft a better wine. So, the next time you're enjoying a glass of wine think about how much art and science went into your bottle.

Happy Tastings!
~Brad

Wild Grapes

Brad Posts:

During the last hot humid days of September, 2007, after having scouted several natural areas over the preceding months, I was rewarded with a nice, albeit very small batch of wild grapes from which I would make my first gallon of wild grape wine.

If you have ever picked wild grapes to make jam, jelly or in my case wine, you'll appreciate the effort it takes. Unlike their trained cousins growing on a chest-high trellis ready for easy picking these tiny, wild rascals grow on old fences, bushes, and climb into the heights of nearby trees. Not easy to find. Not easy to pick. Add to that the mosquitoes, briers, and poison ivy -- now we're talking fun!

Seriously though, making wine from wild grapes is satisfying - both in terms of the amount of effort required and the wine made/consumed. The fact IS not many folks take the time to make wild grape wine. I remember when we bottled those first few bottles of Wild Grape wine last year and after sampling a bit I was shocked...shocked by how good and earthy it was.

Early last summer, my brother drove the 1,100 miles from Maryland for a visit with us (he was here for a crush party too - of fresh grapes from Chile). Later that night I opened the first bottle (of 5) of our Wild Grape and we sat on in our 3-season porch on a pleasantly warm evening and sampled the wine (13.5% alc). Just like I remembered -- yummy! By bottles end it was about time for bed.

After the Eastern Iowa floods of 2008 we scoured the landscape for wild grapes, but many of the locations we had from the year before were inundated with water and did not produce grapes this year. With the help of a friend, he led us to his fathers house south of Des Moines where we were to harvest wild plums...instead we found a good supply of wild grapes. We ended up harvesting over 26 pounds (post stemming) and placed the grapes into my freezer to wait until winter to begin fermentation. So today, on a -8F sunny Saturday, we freed the wild grapes to begin thawing. In a day or so (when the must is warmed enough) we'll introduce the yeast and wait for the onset of fermentation.

I'm excited about working with these grapes and feel grateful I can borrow from the natural areas of Iowa and craft a truly unique wine.

Cheers!
~Brad

Iowa and Wine?

Brad posts:

There is an old and tired joke among people who dabble in wine, it goes something like this: “Do you know how to make a small fortune in the wine business? Start with a large fortune.” Although I suppose there is more than a little truth to the dry wit of my wine-brethren, I still cannot help but cringe every time I hear that oaky passage. Alas, I must admit to the lure of bug-infested vineyards whose heavily fruit laden loads tease me with a waft of what might be. And as much as I am tempted by the green oasis and the constant attention demanded of the vineyard, I am also drawn to the back-breaking tedium of the crush as the grape-must calls out to me with her yeasty aroma!

Wine may not be “in my blood”, but I suspect there is a DNA marker hidden in my genes for some lone biologist to uncover after my last crush. In the past few years I have spent nearly all of my free time either making wine, reading about making wine, or taking winemaking classes… and of course enjoying a sip or two as I uncover the secrets of enology.

And of all places…in Iowa!

It is here, in the heartland, nestled among the cornfields and hogs, where the beginning of something impressive can be felt. Unless you have paid close attention, it is doubtful many outside of our modest Midwestern vineyards and wineries have noticed the accolades from international wine judges. Fine wines are now being made from grapes you may never have heard of before, such as Chambourcin, Marechal Foch, Norton, Frontenac, Marquette, St. Croix (some of the reds); and La Crosse, St. Pepin, La Crescent, Brianna, Frontenac Gris, and Seyval Blanc (some of the whites).

The grapes we raise for our wines must be, not unlike good Midwestern stock, hardy in order to make it through very cold winters. These grapes are made for extreme weather! Thanks to the researchers at the Univ. of Minnesota a new varietal called Marquette, a cousin of Frontenac and grandson of Pinot noir, can handle temperatures as low as -35F and still produce a crop – not to mention make excellent wine.

The good fortune joked about earlier may not be in the size of the winery or the funds needed to start, but the good fortune may be yours when you try something new (and yes, from Iowa) and find it to be delicious!

Cheers! ~Brad