This information is provided as a service by Texas A&M AgriLife Extension Service with partial funding from the High Plains Winegrowers Association. Texas A&M AgriLife Extension Service is not responsible for any damage or loss resulting from the use or misuse of this information.

REAL-TIME MONITORING

Critical temperatures for wine grapes are determined using a method called “differential thermal analysis”.  These data are updated approximately weekly from December through March. Data is collected from approximately 60 buds total (node positions 3 to 8) from at least 10 canes per variety on mature vines grown in vineyards in the Texas High Plains AVA.

LT10 = temperature at which 10% of the primary buds will be killed.

LT50 = temperature at which 50% of the primary buds will be killed.

LT90 = temperature at which 90% of the primary buds will be killed.

MAXT = maximum temperature recorded for the day.

MINT = minimum temperature recorded for the day.

If the temperatures recorded for the day decline below the critical temperature (LT), then bud damage has likely occurred. Please review the Grapevine Cold Hardiness factsheet for information on managing cold-damaged vineyards.

Buds are collected from vineyards in Lubbock and Brownfield, Texas.

12/8/2021	LTE10 (⁰F)	LTE50 (⁰F)	LTE90 (⁰F)
Alvarinho	6.78	4.28	1.74
Cabernet-Sauvignon	11.12	7.74	3.63
Carignan	10.04	5.45	2.71
Mourvedre	7.83	5.07	2.30
Petite Sirah	11.79	7.43	2.34
Touriga nacional	11.39	7.57	4.71
Vermentino	10.20	6.80	2.07
Viognier	7.09	1.89	-1.93
12/15/2021
Cinsault	12.18	7.29	1.96
Marsanne	11.61	2.79	-1.14
Piquepoul blanc	14.34	8.92	3.18
Roussanne	10.47	5.25	1.42
Sangiovese	6.62	2.73	-0.63
Tempranillo	12.56	8.26	3.22
12/22/2021
Alvarinho	3.76	0.72	-2.04
Cabernet-Sauvignon	6.60	3.15	0.01
Carignan	2.84	0.45	-2.02
Mourvedre	3.02	-0.09	-3.03
Petite Sirah	10.20	6.53	2.62
Touriga nacional	8.15	4.62	1.53
Vermentino	6.30	2.55	-0.56
Viognier	5.58	0.72	-2.67
12/29/2021
Cinsault	7.54	1.08	-2.85
Marsanne	5.16	-0.09	-2.42
Piquepoul blanc	6.51	3.15	1.33
Roussanne	8.01	3.22	-0.02
Sangiovese	6.22	2.39	-0.80
Tempranillo	9.12	5.81	-0.58
1/4/2022
Alvarinho	-1.43	-4.79	-7.55
Cabernet-Sauvignon	3.20	-0.69	-5.71
Carignan	2.23	-2.43	-6.39
Mourvedre	1.53	-2.88	-7.35
Petite Sirah	5.25	1.36	-1.52
Touriga nacional	3.79	1.08	-2.34
Vermentino	1.98	-2.36	-5.30
Viognier	-0.49	-4.02	-7.04
1/12/2022
Cinsault	1.36	-0.89	-4.31
Marsanne	1.53	-1.68	-4.32
Piquepoul blanc	2.17	-0.87	-4.11
Roussanne	0.27	-3.51	-8.25
Sangiovese	0.37	-3.01	-6.68
Tempranillo	4.46	1.85	-3.53
1/19/2022
Alvarinho	-3.53	-6.90	-10.88
Cabernet-Sauvignon	-1.03	-2.60	-6.11
Carignan	-2.16	-5.75	-7.76
Mourvedre	-3.12	-6.09	-9.51
Petite Sirah	-1.64	-4.43	-5.89
Touriga nacional	-0.11	-3.69	-6.88
Vermentino	-2.54	-4.83	-7.78
Viognier	-4.04	-6.66	-10.66
1/25/2022
Marsanne	-1.16	-2.70	-5.01
Piquepoul blanc	-2.34	-3.53	-5.39
Tempranillo	0.28	-2.29	-5.37
2/1/2022
Alvarinho	-5.67	-10.41	-13.72
Cabernet-Sauvignon	-4.50	-5.44	-6.14
Carignan	-4.47	-6.86	-8.57
Mourvedre	-5.55	-7.78	-10.91
Petite Sirah	-5.17	-5.73	-6.52
Touriga nacional	-3.46	-5.15	-8.00
Vermentino	-3.69	-7.13	-10.35
Viognier	-4.47	-7.38	-10.14
2/9/2022
Marsanne	-5.49	-7.26	-8.21
Piquepoul blanc	-4.56	-5.51	-6.48
Tempranillo	-5.35	-6.97	-8.61
2/16/2022
Alvarinho	-1.84	-6.59	-12.01
Cabernet-Sauvignon	-1.01	-4.63	-5.89
Carignan	-2.52	-6.36	-8.63
Mourvedre	-4.00	-7.60	-10.82
Petite Sirah	-0.85	-2.29	-5.26
Touriga nacional	-3.77	-6.84	-9.56
Vermentino	-0.11	-5.03	-8.55
Viognier	-3.26	-5.62	-8.88

Texas A&M AgriLife Extension Service – Viticulture and Enology Team (Texas A&M University) is looking for a full-time Master’s Student to join our group for a two-year research project with the main focus on Enology and with an important Viticulture component. The position is funded, and it involves living and studying in College Station (main campus) as well as traveling and performing research a few times a year in Lubbock, TX.

Start Date

January 2022

Project Title

Verjus: A natural method to improve wine acidity and increase the profitability of grape production in Texas

Project Summary

Verjus, the acidic juice produced from unripe grapes, has a very long history of culinary use. Researchers at the Texas A&M AgriLife Extension Service and Texas Woman’s University seek to evaluate the potential of using verjus to naturally acidify Texas wine, addressing a common winemaking challenge of high pH, while simultaneously providing grape growers with an additional source of income for the fruit that is normally removed prior to harvest, but discarded. The goals of the project are:

1) assess the feasibility of verjus production by cluster thinning using a mechanical harvester.

2) determine the impact of verjus on white wine chemical composition and flavor quality.

The trial will be conducted in a commercial vineyard in Brownfield, Texas. Grapes will be processed to verjus and resulting wine. The verjus and wine quality and flavor properties will be characterized using instrumental analysis and sensory evaluation.

The outcomes of this project will help improve Texas wine quality and serve to enhance the competitiveness and longevity of grape production in the state.

Contacts

Dr. Pierre Helwi : pierre.helwi@ag.tamu.edu

Dr. Andreea Botezatu : andreea.botezatu@ag.tamu.edu

Date: December 3, 2021

Location: Hildebrand Equine Complex, College Station, Texas

Sponsorships – To purchase a sponsorship, click here or contact one of the specialists.

Registration is open at https://agriliferegister.tamu.edu/Viticulture