About

Amanda C. Stewart is an Associate Professor in the Food Science & Technology department at Virginia Tech. She holds a Ph.D. in Food Science from Purdue University, obtained in 2013, along with a Master’s degree in Agricultural and Biological Engineering (2004) and Bachelor’s degrees in Agricultural and Biological Engineering and Biochemistry (2003), both from Purdue University. Her research focuses on food and beverage fermentation, particularly working with wine and hard cider quality, and examining how fermentation processes impact bioactive compounds relevant to human health. She collaborates with horticulture researchers to develop vineyard and orchard management practices aimed at improving wine and cider quality, and investigates the effects of processing methods on cider chemistry and quality. Her current projects include studying the impact of yeast assimilable nitrogen on fermentation, the influence of juice clarification on fermentation and polyphenol content, and exploring fermented vegetables and their health benefits. Stewart is also responsible for teaching courses such as Wines and Vines, and Functional Foods for Health.

Research topics

• Chemistry
• Food science
• Pulp and paper industry
• Environmental science
• Waste management
• Engineering
• Organic chemistry
• Biology
• Environmental chemistry
• Biotechnology
• Agronomy
• Environmental engineering
• Horticulture

Selected publications

• Evaluating the Persistence of <i>Salmonella enterica</i> Tennessee and <i>Levilactobacillus brevis</i> in Non-Alcoholic Beer Under Low Pasteurization

  Journal of the American Society of Brewing Chemists · 2026-02-12 · 1 citations

  article
  PublisherDOI

• Evaluating the Persistence of <i>Salmonella enterica</i> Tennessee and <i>Levilactobacillus brevis</i> in Non-Alcoholic Beer Under Low Pasteurization

  Open MIND · 2026-02-12

  article

  Non-alcoholic (NA) beer (&lt;0.5% ABV) can support the survival of foodborne pathogens such as <i>Salmonella</i>. Typical recommendations for NA beer pasteurization (73.9 °C for 1 min or 80–120 PU) can help ensure food safety, but producers do prefer lower temperatures to preserve product quality. This study evaluated the impact of a lower heat treatment (52 °C for 1 min; ∼0.75 PU) on the survival of <i>Salmonella enterica</i> subsp. <i>enterica</i> serovar Tennessee in NA beer over six months and assessed the impact of co-inoculation with a spoilage organism, <i>Levilactobacillus brevis</i>. NA beer was inoculated with <i>S.</i> Tennessee (∼8.0 log CFU/mL) only or co-inoculated with <i>L. brevis</i> (∼8.0 log CFU/mL) and subjected to three pasteurization treatments: typical (73.9 °C for 1 min), low (52 °C for 1 min), and no pasteurization. Samples were stored at 14 °C and analyzed over six months. Significant differences were observed between pasteurization treatments post-pasteurization where <i>Salmonella</i> populations in the <i>Salmonella</i>-only samples reduced by 8.07 ± 0.00, and 2.25 ± 0.13 log CFU/mL for the typical and low samples, respectively. Similarly, post-pasteurization <i>Salmonella</i> populations in the co-inoculated samples reduced by 7.96 ± 0.00, 2.15 ± 0.83, and 0.00 ± 0.00 log CFU/mL for the typical, low, and no pasteurization samples, respectively. After 183 days, <i>Salmonella</i> persisted in the low and no pasteurization samples. There were no significant differences observed due to co-inoculation. Findings show that <i>Salmonella</i> can survive for at least 183 days in NA beer under low pasteurization conditions and can survive despite the presence of a common spoilage organism.

  DOI

• Evaluating the Persistence of <i>Salmonella enterica</i> Tennessee and <i>Levilactobacillus brevis</i> in Non-Alcoholic Beer Under Low Pasteurization

  Figshare · 2026-02-12

  articleOpen access

  Non-alcoholic (NA) beer (&lt;0.5% ABV) can support the survival of foodborne pathogens such as <i>Salmonella</i>. Typical recommendations for NA beer pasteurization (73.9 °C for 1 min or 80–120 PU) can help ensure food safety, but producers do prefer lower temperatures to preserve product quality. This study evaluated the impact of a lower heat treatment (52 °C for 1 min; ∼0.75 PU) on the survival of <i>Salmonella enterica</i> subsp. <i>enterica</i> serovar Tennessee in NA beer over six months and assessed the impact of co-inoculation with a spoilage organism, <i>Levilactobacillus brevis</i>. NA beer was inoculated with <i>S.</i> Tennessee (∼8.0 log CFU/mL) only or co-inoculated with <i>L. brevis</i> (∼8.0 log CFU/mL) and subjected to three pasteurization treatments: typical (73.9 °C for 1 min), low (52 °C for 1 min), and no pasteurization. Samples were stored at 14 °C and analyzed over six months. Significant differences were observed between pasteurization treatments post-pasteurization where <i>Salmonella</i> populations in the <i>Salmonella</i>-only samples reduced by 8.07 ± 0.00, and 2.25 ± 0.13 log CFU/mL for the typical and low samples, respectively. Similarly, post-pasteurization <i>Salmonella</i> populations in the co-inoculated samples reduced by 7.96 ± 0.00, 2.15 ± 0.83, and 0.00 ± 0.00 log CFU/mL for the typical, low, and no pasteurization samples, respectively. After 183 days, <i>Salmonella</i> persisted in the low and no pasteurization samples. There were no significant differences observed due to co-inoculation. Findings show that <i>Salmonella</i> can survive for at least 183 days in NA beer under low pasteurization conditions and can survive despite the presence of a common spoilage organism.

  PublisherDOI

• Yeast Nutrient Supplementation Influences Cider Chemistry and Consumer Preference for Naturally Fermented Cider, While Information About Production Practices Does Not Influence Consumer Preference

  Journal of the American Society of Brewing Chemists · 2025-08-15

  articleSenior authorCorresponding
  PublisherDOI

• Development of a hard cider flavor wheel using free word sorting and multivariate statistical techniques

  Journal of Sensory Studies · 2024-04-01 · 9 citations

  articleOpen access

  Abstract Flavor wheels are visual tools built from standardized sensory lexicons that are used in many different industries to improve communication, marketing, and quality discrimination among products. To date, flavor wheels have been developed for spices, coffee, wine, beer, and many other foods and beverages—yet no flavor wheel has been constructed for hard cider. While there is no single established method for constructed flavor wheels, most approaches are based on sensory descriptive analysis (DA) and free word sorting activities that investigate the semantic similarity and dissimilarity of descriptive terms. This research study utilized multiple DA studies for the generation of a sensory lexicon, followed by independent word sorting tasks with cider industry professionals ( N = 40) and untrained consumers ( N = 58) to establish two flavor wheels that are broadly understandable to a variety of industry stakeholders. Based on the results of DISTATIS and additive tree partitioning, this research showcases a workflow for developing and refining flavor wheels that incorporate both stakeholder and researcher input and can be built upon by other analysts. Practical Applications This research demonstrates an accessible methodology for developing flavor wheels that incorporates input from diverse parties and considers the semantic associations of terms used by cider consumers and industry professionals. The proposed methodology is a useful framework for other sensory scientists seeking to efficiently develop flavor wheels for multiple audiences. As a demonstration, this research also delivers two flavor wheels—one that highlights discrepancies in how industry consumers and producers semantically understand sensory experiences compared to trained sensory personnel, and a second wheel that showcases how hard cider can more objectively be described. Together, these flavor wheels are tools for improving sensory communication, education, and marketing in the US hard cider industry.

  PublisherDOI

• Foliar urea applications to apple trees increase yeast assimilable nitrogen, amino acids, and flavor volatiles in fruit and hard cider

  Journal of Agriculture and Food Research · 2024-03-27 · 9 citations

  articleOpen access

  Volatile compounds are a crucial component of hard apple (Malus ✕domestica Borkh.) cider aroma, flavor, and consequent marketability. Amino acids are used by Saccharomyces cerevisiae yeast in the production of volatiles and their precursors. This study hypothesized that foliar applications of nitrogen to apple trees would elevate the concentration of amino acids in the fruit, thus increasing the concentration of sensorially distinguishable aromatic volatiles in cider. In this experiment, urea foliar fertilizer was applied to ‘Ellis Bitter’ and ‘Harry Masters Jersey’ apple trees to create Control (0 applications), Low (3 weekly applications), and High (5 weekly applications) treatments. Total leaf nitrogen increased with the number of foliar urea applications, demonstrating plant uptake. The total fruit yield and fruit efficiency (total harvested fruit mass relative to trunk cross-sectional area) did not differ among treatments within the same cultivar. Similarly, fruit maturity, size, total phenolics, pH, and soluble solids concentration did not differ among treatments. Yeast assimilable nitrogen (YAN) and amino acids in the juice increased with the number of foliar urea applications, as did fermentation rates. Relative to the Control, the High treatment had 130% greater YAN in ‘Ellis Bitter’ and 145% in ‘Harry Masters Jersey’. Over 90% of the YAN in all juice samples was composed of primary amino nitrogen (PAN), and the majority of the PAN among all treatments was asparagine. Ester and fatty acid content in hard ciders increased with the number of urea applications; however, higher alcohols showed a mixed relationship with the number of applications in the cultivar ‘Ellis Bitter’. Aroma and flavor differences among treatments were discernible by triangle discrimination test panelists; however, the sensory differences were not easily identifiable with untrained panelists. This study demonstrated that late season foliar urea applications to apples trees can increase juice YAN and aromatic compounds in finished cider.

  PublisherDOI

• Exploring cider website descriptions using a novel text mining approach

  Journal of Sensory Studies · 2023-05-30 · 8 citations

  articleOpen access

  Abstract Rapid methods of text analysis are increasingly important tools for efficiently extracting and understanding communication within the food and beverage space. This study aimed to use frequency‐based text mining and biterm topic modeling (BTM) as tools for analyzing how cider products are communicated and marketed on cider‐producer websites for products made in Virginia, Vermont, and New York. BTM has been previously used to explore topics in small corpora of text data, and frequency‐based text mining is efficient for exploring patterns of text across different documents or filters. The present dataset comprised 1115 cider products and their website descriptions extracted from 124 total cider‐producer websites during 2020 and 2021. Results of the text mining analyses suggest that cider website descriptions emphasize food‐pairing, production, and sensory quality information. Altogether, this research presents the text mining approaches for exploring food and beverage communication. Practical applications This research will be valuable to stakeholders in the United States' cider industry by providing relevant insight as to how cider marketing and sensory communication varies based on extrinsic product factors, such as geography and packaging. This research also demonstrates the efficiency and potential of text mining tools for exploring language and communication related to foods, beverages, and sensory quality. Further, this research provides a framework for extracting sensory‐specific language from a large corpus of data, which may be adopted by other researchers wishing to apply rapid descriptive methods in the sensory, quality, and consumer research fields.

  PublisherOA PDFDOI

• “The uniqueness of one apple versus another.” Exploring producer perspectives of hard cider in the Northeast and Mid-Atlantic United States

  Food Culture & Society · 2023-10-25 · 3 citations

  articleOpen access

  Hard cider is growing in popularity throughout the United States (US). Though many scholars have investigated quality and trends in the expanding US cider industry, still little is known about cider producers’ opinions of the products that they make. How do American cider producers value and emplace value onto cider as the industry grows and competes with the broader alcoholic beverage market? This study explored producer perceptions of American hard cider by employing 21 semi-structured interviews with cider-makers throughout Virginia, Vermont, and New York – three leading cider producing states in the Northeast and Mid-Atlantic US. Interview sessions were subject to reflexive thematic analysis for themes related to preference, consumption, and cider-making. Results suggest that cider producers broadly prefer complex flavors and cider made with cider-specific apples. Yet, cider producers ascribe to a diverse spectrum of values related to the cider-making process, agriculture, and business goals, which influence their preferences and the experiences that they create for other consumers. This research also identifies a chasm in how American “cider” is being constructed and valued, offering broad implications for the domestic cider and apple agriculture industries as well as a template for bridging the divide between producer- and consumer-based food studies.

  PublisherOA PDFDOI

• Appeal of the Apple: Exploring Consumer Perceptions of Hard Cider in the Northeast and Mid-Atlantic United States

  Journal of the American Society of Brewing Chemists · 2023-10-23 · 3 citations

  articleOpen access

  Alcoholic or “hard” cider is experiencing a resurgence in popularity, particularly throughout the Northeast and Mid-Atlantic regions of the United States. Yet, many stakeholders struggle to understand how consumers define and distinguish hard cider from the sea of options in the saturated alcoholic beverage market. This study aimed to explore consumer preferences for hard cider using a phenomenological, qualitative approach. The research comprised 14 focus groups with regular cider consumers (99 participants) throughout three leading cider-producing states in the Northeast and Mid-Atlantic United States: Virginia, Vermont, and New York. All focus group sessions were subject to reflexive thematic analysis for themes broadly related to cider product preference and the cider-drinking experience. Results of the study suggest that cider preference is motivated largely by sensory quality in addition to various other factors including perceived health effects, regionality and proximity, the drinking occasion, and product information. Results also emphasize the importance of nostalgia in cider sensory experiences, as well as the role of social norms in consumer valuation of cider products. Overall, this research highlights diverse consumer preferences for cider and serves as a framework for using qualitative research methods to explore consumer preferences in the food and beverage industries.

  PublisherOA PDFDOI

• Sensory descriptive analysis of hard ciders from the Northeast and Mid‐Atlantic United States

  Journal of Food Science · 2023-02-28 · 7 citations

  articleOpen access

  Although alcoholic or "hard" cider is a beverage of growing popularity throughout the Northeastern and Mid-Atlantic United States (US), the industry lacks a consistent language for describing the sensory quality of its products. The main objective of this research was to explore the sensory attributes that can be used to describe a large representative sample (N = 42 samples) of ciders from Virginia, Vermont, and New York, using classical descriptive analysis (DA). The secondary objective of the research was to determine if cider samples' sensory attributes differ based on extrinsic factors, such as style, packaging, and apple varieties. The study was conducted using a standard DA: 8 panelists were trained for 13 h to develop a lexicon of aroma, taste, and mouthfeel descriptors for 42 cider samples (15 single varietal ciders, 27 blended ciders). Then, subjects evaluated each cider in duplicate for all descriptive attributes in standard sensory-evaluation conditions. Results were analyzed to determine overall differences among the individual cider samples, geographic origins, cider styles, and packaging formats, as well as significant differences across individual attributes. Herein, we report on 29 attributes that can be used to discriminate cider samples, as well as a subset of attributes which differentiate ciders based on extrinsic product variables. These results provide a framework for describing ciders from the Northeast and Mid-Atlantic regions of the US, which may be further generalizable to other North American ciders. As well, these results highlight the potential for more descriptive, sensory-based style guidelines may inspire future research related to cider production practices and terroir.

  PublisherOA PDFDOI

Frequent coauthors

• Andrew P. Neilson

  North Carolina State University

  38 shared

• Gregory M. Peck

  31 shared

• Sihui Ma

  University of Illinois Urbana-Champaign

  28 shared

• Sean F. O’Keefe

  Virginia Tech

  17 shared

• Brianna L. Ewing

  Black & Veatch (United Kingdom)

  16 shared

• Jacob Lahne

  Virginia Tech

  13 shared

• Anna Katharine Mansfield

  Cornell University

  10 shared

• Clinton L. Neill

  Cornell University

  9 shared