Summary 

This study examined how blending apple and grape pomace—the pressed fruit solids left over from juice and wine production—can be used to create novel fermented beverages like ciderkin, piquette, and hybrid ciderkin-piquette. By adding water to pomace, residual sugars and flavors are extracted, enabling a second fermentation. Using ‘McIntosh’ apple and ‘Frontenac gris’ grape pomace, researchers tested how different blend ratios affect fermentation, chemistry, color, and nutritional value. Grape pomace increased sugar, nutrients, and acidity, leading to faster fermentation, higher alcohol, and more antioxidants. Apple pomace contributed more aroma-related volatile acids but lacked nitrogen, requiring yeast nutrient supplementation for complete fermentation. All blends had sufficient acidity (pH < 3.5) for safe fermentation without added acid. Grape pomace enhanced red color and polyphenol content, while apple pomace added yellow tones and unique health-promoting compounds. These findings support pomace blending as a sustainable, value-added strategy for producing flavorful fermented beverages. 

Introduction 

Ciderkins (made from apple pomace) and piquettes (made from grape pomace) are flavorful, lower-alcohol beverages that are gaining popularity with consumers seeking sustainable and health-conscious options. The growing appeal of these “second” ferments offers wineries and cideries a promising opportunity to turn leftover pomace—typically a waste product—into a value-added revenue stream. 

On their own, piquette and ciderkin can sometimes lack balance in flavor or aroma. However, blending these two pomace types offers a way to harmonize sugar, acidity, color, and aromatic qualities—creating a more appealing and well-rounded beverage. This study introduced a novel hybrid drink, ciderkin-piquette, by co-fermenting apple and grape pomace. Although each has been used separately in second-fermentation beverages, their combined use has not been previously studied.  

This study used ‘Frontenac gris’ grape pomace—which contributes bright acidity, red-pink pigmentation, and antioxidant-rich compounds—and ‘McIntosh’ apple pomace, which adds natural sweetness, malic acid, and warm caramel-like tones. Different blend ratios were evaluated for their influence on fermentation behavior, final chemistry, color characteristics, and nutritional composition—providing practical insights for producers interested in turning fruit byproducts into sustainable, value-added beverages.

‘McIntosh’ apples and ‘Frontenac gris’ grapes were harvested from orchards at Montana State University Western Agricultural Research Center in Corvallis, MT. Apples were ground, and grapes were destemmed and crushed before pressing. Pomace was collected after pressing and frozen until use. Five treatments were created using different apple-to-grape pomace ratios: 

GA1: 100% grape pomace 

GA2: 100% apple pomace 

GA3: 75% grape, 25% apple 

GA4: 25% grape, 75% apple 

GA5: 50/50 blend 

Traditional ciderkin and piquette production typically involves minimal water—just enough to cover the pomace—and does not include adding sugar, resulting in lower alcohol content. The pomace-water mixture is often pressed before fermentation begins. However, this study used a more controlled and enriched fermentation approach to evaluate the potential of blended pomace beverages.  

Each treatment was prepared by combining pomace with water at a 1:3 pomace-to-water ratio and adjusting the sugar content to 15 °Brix. Fermentation was initiated using the commercial wine/cider yeast strain Exotic Mosaic and conducted on the skins for four days before pressing. Throughout fermentation, sugar depletion, pH, color development, and nutrient levels were monitored. Final products were analyzed for alcohol concentration, acidity, glycerol content, total phenolics, and antioxidant activity.

Fermentation Behavior 

  • Grape pomace led to much faster fermentation due to higher levels of nitrogen that the yeast use, known as yeast-assimilable nitrogen (YAN), and slightly higher alcohol (up to 8.1% Alcohol by Volume=ABV compared to 7.9% ABV in the apple pomace alone). 
  • Apple pomace slowed fermentation and required reinoculation due to low nitrogen and sugar.  Apple are know to have low YAN and ciderkin had even lower levels (<5ppm).   
  • Grape pomace provided more yeast-assimilable nitrogen (YAN) and tartaric acid, while apple pomace had higher glucose-to-fructose ratios. 

Color Changes 

  • Grape pomace added red tones (higher a* values), while apple pomace contributed yellow hues (higher b* values). 
  • Lightness (L*) decreased with more grape pomace, resulting in darker, more wine-like colors. 
  • These color dynamics suggest grape pomace could be used to create rosé-style ciders without red-fleshed apples. 

Final Composition 

  • Alcohol: Highest in grape-heavy blends (GA1, GA3). 
  • Glycerol: Highest in GA1, contributing to smoother mouthfeel. 
  • Volatile acids: Highest in apple-heavy blends (GA2), affecting aroma and sharpness. 
  • Residual sugars: More glucose remained in apple pomace blends, suggesting yeast strain preferences. 

Phenolic Content & Antioxidant Activity 

  • Grape pomace significantly increased total phenolics and antioxidant capacity. 
  • GA1 had five times more phenolics than GA2. 
  • Antioxidant activity (measured by FRAP and DPPH assays) was highest in grape pomace wines, with FRAP showing greater sensitivity. 

Specific Phenolic Compounds 

  • Grape pomace contributed: 
    • Catechin, epicatechin, gallic acid, resveratrol, kaempferol, procyanidin B2 
    • Known for cardiovascular, anti-inflammatory, and anticancer benefits 
  • Apple pomace contributed: 
    • Chlorogenic acid, vanillic acid, quercetin-3-galactoside, apigenin, luteolin 
    • Associated with blood sugar regulation, immune support, and antioxidant effects 
  • Blended treatments showed diverse phenolic profiles, with potential for functional food applications. 

Conclusions 

Ciderkins, piquettes, and hybrids offer a promising approach to creating sustainable, health-enhancing fermented beverages. Each pomace type contributes distinct benefits: grape pomace improves fermentation efficiency, color, and antioxidant content, while apple pomace adds fermentable sugars, unique flavors, and additional bioactive compounds. 

When fermented together, these pomaces produce balanced products with improved functional properties like stable acidity and enhanced antioxidant activity. This co-fermentation strategy not only helps reduce fruit processing waste but also opens the door to developing low-alcohol, nutrient-rich drinks that appeal to health-conscious consumers. 

Beyond traditional beverages, fruit pomace can be used to create natural food colorings or processed into extracts rich in bioactive compounds. These extracts may have potential applications in functional foods, dietary supplements, or even pharmaceuticals. With further research, these fermentation methods could be adapted for low- or non-alcoholic products, expanding their usefulness across multiple industries.   

Funding Acknowledgement 

This research is funded by Montana Department of Agriculture. Grant No: AM22SCBPMT1127.