fermentation


sugar concentrationEver wonder what it is in sugar that makes our kids run around like crazy? Or why we like it in all forms?  Well, I don’t have the answers here, sorry. But, I do have an opinion about high sugars in grapes. Maybe they are somehow related. 

I just came back from a seminar put on by the Napa Valley Grape Growers association. The main topic was different, but the high sugar topic was top of mind and kept on creeping into the discussion.

In the last few years, there seems to be a preference for higher alcohol levels in red wines. There seems to be a market preference, which might be driven by a reviewer’s preference and in some cases this leads winemakers to cater to that preference.  This means picking grapes later to allow the sugar level in the grapes to increase relative to the overall weight of the grapes (measured in Brix). The phenomena is called Letting it Hang. An increase in Brix level ultimately results in an increase in alcohol level in the wine. If you noticed, I am being very careful with my words.  There is more and more evidence that the increase in sugar level is not because the vine is producing more sugar but because the clusters are dehydrating, therefore increasing the ratio of sugar to the rest of the grape cluster weight. This is a trick the Italians play with their intoxicating Amarone, except they dehydrate the grapes after they pick them.

Why does it matter? Two main reasons:

  1. As the grapes shrink due to dehydration, the growers that get paid by the ton get short changed–that’s most of them.
  2. Winemakers that pick very late with high sugar levels risk picking grapes with low acids and high PH. Resulting in either an unbalanced wine, or perhaps worse–a wine that has to be manipulated to bring it back into balance.

Why do I think it should matter to wine drinkers?  well, at least in my opinion, high alcohol wines typically result in heavy, full body, over the top, prune flavors in the wine. None of the subtle elegance that a classic food friendly wine can and should provide. My taste buds, my preference, your opinion may vary. 

This article, in the New York times by Eric Asimov, which was forwarded to me by multiple friends, does a much better job describing the style of wine I am talking about. It also includes a list of wineries producing some of these classically elegant wines.

Back to my post, just like sugar, high alcohol wines, can bring me crashing down 30 minutes later and wanting for a more balanced wine.

Chromotagraphy test fro malo conversion

chromotography test

This weekend we performed the chromotagraphy tests on our Las Brisas Pinot Noir and Pinot Noir rose. I am happy to report that the Malo-lactic, or ‘Malo’ conversion is complete–right on schedule.  Just like in the previous five years, by the time the first week of November rolls around, the little bugs have done their job. Basically wine contains a few different kinds of acids, Tartaric is one and Malic another.  There are others but not in high enough quantities to be noticed.  During malo conversion (also referred to as Secondary Fermentation) Malolactic bacteria eat away at the Malic acid and covert it to Lactic acid and Carbon Dioxide.  Being about half as strong as Malic acid, Lactic acid is softer on the pallet. The total effect is reduction in total acidity and a rounder softer, mouth feel. For a real technical description see here.  In my opinion it has been overdone in many California Chardonnays and I do not like it in that varietal.  However, many red wines benefit and are enhanced by it, so we pursue it with our Pinot.  In addition to the reduction of acid, it stabilizes wine and should be done before bottling. If you bottle before Malo conversion is complete, it might be triggered spontaneously when the weather warms up.  This will put the bugs in motion, only this time while they are enclosed in a bottle. You will end up with ugly deposits, aromas and fizz that could potentially push out corks. 

Which gets me back to Chromatography, how do you know when ‘malo’ is done? At the winery we take a sample and send to the lab.  A day later we get an email that tells us the Malic acid content in grams per liter.  If it is under a certain number, i.e. .09 grams per liter, it is done! Easy.

At home, we get to play Mad Scientist and do our own fun, chromotography test.  Ben and I just did one this weekend and the image you see here shows the results.  

We dot a special paper with wine samples and reference acids (Tartaric and Malic in this case.)  Then we put the paper in a special ‘developer’ liquid for 8 hours and watch the liquid travel up the paper. As it travels up it carries with it the different acids to different levels.

Tartaric is at the bottom third, Malic is in the middle and Lactic is at the top. The acids from the wine sample travels up the paper as well.  The test is to observe and see if the wine sample has a spot at the same level as the Malic spot. If it does, Malic conversion did not take place; if the spot is faint, it is only part way done. If there is no spot, Malo is done!  

Chromotagraphy test fro malo conversion

ooh, pretty

Look at the image again.  There are six columns.  The spot in the far left column is the Tartaric reference; the second is the Malic reference; the third, fourth and fifth columns are the Pinot Noir samples from three different vessels; the last is our Pinot Noir rose. This means that Malo is done for the three Pinot reds–note there are no yellow spots at the same level as the Malic reference dot (mid way thru the paper hights). The Rose however, did not go thru Malo.  This is a good thing because we like Rose more acidic, that’s what makes it more refreshing served chilled on a hot afternoon.

If there are winemaker scientists out there wondering what the light dot above the Tartaric and the light dot below the Malic references are, well, my guess is that it is a bit of contamination from the reference solutions while I was preparing the tests. Unless someone else has a different explanation.  I did not see these in previous years.  In any case, whether malo conversion took place or not, it makes a nice piece of psychedelic, abstract art to hang on the cellar walls. 

Monday we pressed the last of our Pinot–this one from Santa Lucia Highland’s Lone Oak Vineyard. This one was easy…

Previous presses at home went on for hours and got us all juicy and ‘winey’ from our wooden basket press squirting, buckets dripping and the occasional kid tripping over and wiping hands all over our pants and shirts. As fun as it is to make wine at home, making wine at the ‘real winery’ is refreshing.

There, forklifts, one-ton bins and giant automatic bladder presses are used.  There, the pressing process goes like this:

Step one: forklift one ton fermentation bin into the air; Step two: use siphon and gravity to fill barrels 3/4 full with free run juice;  Step three: dump, using forklift, rest of must into the press;  Step four:  push button to start automatic press.

Best part:  the smell of a brand new French Oak barrel both before and after filling it…Promises of heaven on earth.  

Get a little closer...
Love the smell of new oak in the morning 

Also good: tasting the press wine as it comes raining down from the press.

That last part is done in steps as we try to figure out at what point we have enough tannins to go into the already barreled wine. When we reach that point, we stop the press and fill the barrels the rest of the way. Done!

Lone Oak is ready to press! Yeah.. Monday we are going to press the Lone Oak Pinot. I was hoping to have this thing go on for longer, however, as usual, the yeast and nature has the final say. We kept the must cold soaking under 50 degrees for about five days after crush. Once we brought it out of the cold room, it took off in no time and the must came up to 80 degrees in two days, then 90 degrees and before we knew it, here we are, five days later and Brix is at almost zero, ready to press. In any case, it followed almost the same trajectory of fermentation of the Sonoma Cost Gap’s Crown pinot, so it should be very interesting to see how it develops.
We are going down to the winery on Monday morning to press and will have some pictures to share from that event.

Uzi

Punching the cap on our home-crafted wine is a piece of cake.  My 9 year old daughter handles it on her own, no problem. Even at age 7 she could do the punch downs in our own cellar where everything is done on a very small scale.  In fact, I would say our cellar is essentially a nano-scaled cellar compared to most licensed wineries.

The punch downs occurring on our Santa Lucia Highlands Pinot Noir right now, for example, are done on a larger scale.  Instead of the garbage can-sized containers we use at home, at the winery we are working with garbage dumpster-sized containers.  Hmmm…I can tell you right now that Uzi will not be happy with my non-technical (not to mention non-appetizing analogies here.)

Anyway, the cap is several inches thick and requires so much pressure to punch through it you cannot imagine.  Some people make it look easy, but it is anything but.  Uzi is working on a more instructional video of punching the cap.  In the meantime, here is a less instructional video of me working hard at it.

Kudos to all the cellar rats doing this grunt work.

~Kathryn

 

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