Thesis
Early harvest wine for the acidification of high pH grape musts
Washington State University
Master of Science (MS), Washington State University
05/2021
DOI:
https://doi.org/10.7273/000004270
Handle:
https://hdl.handle.net/2376/125237
Abstract
Early Harvest Wine (EHW) is produced from pre-mature grapes and is a blending tool that can be used to acidify mature grape musts. EHW blending was investigated for its potential to acidify high pH red wine fermentations, as can occur in warm growing regions such as Eastern Washington State. EHW produced from Washington merlot grapes harvested at pH 2.9 was blended with pH 4.3 merlot grapes (12% v/v); this acidification method was compared with a non-acidified control and a 1.5 g/L tartaric acid treatment. Two inoculation methods, a co-inoculated treatment with yeast and bacteria and a treatment inoculated with yeast only (no bacteria) were evaluated for each acidification method. Beginning after one year, wines were analyzed for basic chemistry, a sensory descriptive analysis, and metabolomics by GC-MS and LC-MS. The EHW treatment introduced higher initial concentrations of malic acid, which produced a smaller pH decrease and more lactic acid after fermentation than in the tartaric acid treatment. The EHW-treated wines were rated lower for fruit aromas and higher for vegetal aromas relative to the other acidification treatments. Metabolite analysis indicated that the EHW treatment had lower concentrations of fruity esters and alcohols, and differed for many unknown observations detected by GC and LC-MS. This was the first time that these alternative inoculation strategies were evaluated with EHW; the chemical and sensory differences between these two methods were small. In conclusion, EHW influenced other sensory properties in the blended musts than acidity and the blending percentage used in this study had less of an effect on pH than pure tartaric acid addition.
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Details
- Title
- Early harvest wine for the acidification of high pH grape musts
- Creators
- Lindsey Mae Kornowske
- Contributors
- James F Harbertson (Advisor) - Washington State University, Food Science, School of
- Awarding Institution
- Washington State University
- Academic Unit
- Food Science, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Identifiers
- 99900896414301842
- Language
- English
- Resource Type
- Thesis