Marquette and Foch grape numbers

[havlikn]

Our Marquette vines were tested today with a vinmetrica 300 and tested 23.2 brix, ph 3.10, ta 1.74%. I'm wondering if those numbers are in line or if my meter is off. It has been a cool year but recently have had above average temps.

Our Foch tested out at 19 brix, 3.12 ph, 1.84% ta.

 

[grapeman]

The meter is way off for TA if pH is right

 

[salcoco]

high ta low ph number looks right to me. the TA number is not in percent but grams per liter. it looks to me that the grapes are not ripe yet. especially the Foch. check again every day also verify color of seeds, ripe grapes will have black seeds very crunchy.

 

[berrycrush]

1.7 g/L sounds really low, but % could mean 17g/L, that is very high

 

[salcoco]

that is correct I forgot to mention the decimal relocation. grapes are still not ripe.

 

[grapeman]

You are right in saying they probably are not right but if Marquette with a pH of 3.1 it would be getting close especially with over 23 brix. The TA here is key with 17 g/L. I think the meter is off- plain and simple and if you are relying on that meter to measure TA you will get a false reading. From 12 years of experience with Marquette I would expect 23 brix and 17 g/L to be still be in the pH to be in the 2.9 range.

The easiest way to tell would be to use a newly calibrated test meter. Either test yours with new reagents or borrow one recently calibrated and compare the two meters readings.

 

[grapeman]

The latest Veraison to Harvest testing numbers should help you see what I am talking about here and I give all credit to the folks at Cornell for this. Here is a section of the test numbers showing Marquette around NY

Marquette
Region Harvest Date Description Ber. Wt. g. % Brix pH TA g/L YAN (ppm)
Champlain 9/11/2017 Champlain 1.00 17.4 2.70 17.6
Champlain 9/11/2017 Champlain 1.45 18.5 2.65 19.7
Finger Lakes 9/11/2017 Dresden 1.48 21.3 3.11 13.8
Finger Lakes 9/11/2017 Ithaca 1.59 18.6 2.83 17.5
Finger Lakes 9/11/2017 Keuka 1.27 23.1 2.94 14.4
Hudson Valley 9/11/2017 Northeast HV 1.55 20.6 3.20 12.9
Hudson Valley 9/11/2017 Northeast HV 1.66 20.1 2.73 15.3
Lake Erie 9/11/2017 Fredonia 1.65 20.6 3.14 14.3
Thousand Islands 9/11/2017 Clayton 1.49 20.1 2.80 18.8
Average 9/11/17 1.46 20.0 2.90 16.0
Prev Sample 9/5/2017 1.45 21.1 2.97 16.3 401​

‘16 Sample 9/12/2016 1.18 23.8 3.11 12.0 278

As you can see the grapes aren't ripe yet with low brix, low pH and screaming high TA, similar to what the OP posted he has. Last year was much warmer than this year and the brix was similar to the OP number of 23 brix and the pH was very similar, but the TA much lower at 12 g/L. This year with similar TA to the OP, brix and pH are much lower. While his numbers might be right what harm is there in checking the mete. Botom line is at the number he gave, they should hang longer.