Marquette Wine Chemistry

Here’s a recap of my first real experience with my Marquette grapes. I had a small harvest the previous year (2008) but I did a field-blend the Marquette and St Croix grapes.

As I indicated in my harvest post, I picked my Marquettes a bit early due to an oncoming rain storm. So, I started with TA of 12.5 g/l (1.25%) and a pH of 3.43 and a 22 Brix. This was close to the average harvest numbers that I read about from test sites.

I added a bit of sugar to get the Brix up to 23 and added 20PPM of SO2. Then I added Lallzyme EX, Opti-Red, 30g of oak chips, 6 grams of Tartaric Acid, some DAP, and some Fermaid. This raised the TA to 13.3 g/l but got the pH down to 3.30 Although I wanted to use D-254 yeast, I forgot to order it so I used RC-212 instead which I had on hand.

I fermented rather warm and pressed the skins after 5 days. The thin skins had given up all they had. The wine was almost fully fermented after 7 days. I added my mlf culture and some Biolees and kept it in the75 temp range for 6 weeks giving it a good stir every few days (and purging the headspace with Nitrogen). My Chromotography test showed that all the malic had converted to lactic as hoped for. As expected, these cold-weather grapes had a lot of malic (due to our shortage of sunshine and long hot summers) so the TA dropped drastically to 7.5 g/l and unfortunately (but also expected) the pH jumped up to 3.85 I added 40 PPM of SO2.

I did not want to go into cold-stabilization with a pH that high (fear of the pH raising further during the process). So, I added 2 g/l of Tartaric Acid (46 grams for a 6 gallon carboy). This got the pH down to 3.54 but as expected the TA rose to 8.4 g/l After cold stabilization, the TA dropped to 7.2 g/l and the pH also dropped down to 3.33 which I is what I had hoped for.

Although the 7.2 TA would be fine and would mellow with time, I decided to try some modifications. I decided to split into 4 batches. Batch “A” was to blend with some Italian wine (a nice Vino-de-Casa) I made the previous year that had a pH of 3.1 and a 6.0 g/l TA. I did a 40% Italian wine to 60% Marquette and ended up with a 3.24 pH and a 6.7 g/l TA. This should be a really nice wine after a bit of ageing.

Batch “B” was a 10% amelioration (RO water). This resulted in a wine of 3.33 pH (no change of course) and 6.5 g/l for TA. The color did not suffer and the taste was still strong so the 10% dilution did not have much of an effect except to lower the TA a bit.

Batch “C” was to add some Potassium bi-Carbonate. This resulted in a wine of 3.5 pH (still okay) and 6.2 g/l of TA. Again, this is a very nice wine.

Batch “D” was no change at all. I left this batch untouched with a pH of 3.33 and 7.2 g/l of TA. With a bit of ageing this too should be a very nice wine.

Now, for the really hard part….. waiting for another 6 to 18 months to see how these taste !!!!

Update re: Winery and new "Mini-Brewery"

Wow! It has been about 6 months since my last post. Time really flies.....

Winemaking activities over the winter are always rather slow and hands-off while waiting for the new wines to "do-their-thing". I hope to post soon with the numbers and actions I've taken over the last 6 months with both the St Croix and Marquette wines. They are really tasting good!!

With all the snow and drifting I have not been able to start any of the winter pruning. Many of my vines are still under several feet of snow.

It's now been about one full year since I started my mini-brewery. I jumped in with both feet and skipped the usual "extract" brewing (from concentrates) and got right into "all-grain" brewing. I have a couple of mash lauter tuns, a couple of propane burners, several pots and a Keggle, a 14lb grain mill, 6 corney-kegs, CO2 tank, beer fridge, etc. I've brewed 16 batches of beer in the past year and am finding this new hobby (obsession?) to be a lot of fun. Now, friends and visitors can enjoy not only a wide variety of wines but can also enjoy up to 6 beers on tap with others available in bottles.