By Kevin Elder and Elizabeth Higley, Windsor Run Cellars
Effects of Accentuated Cut Edges Processing on Cabernet Sauvignon
Summary
Accentuated Cut Edges (ACE) is a red wine maceration technique that increases the extractable surface area of grape skins. It has been reported to increase phenolic extraction from red grape skins resulting in positive sensory characteristics in the resulting wine1. In this study ACE was performed on Cabernet Sauvignon with the use of an immersion blender. The resulting wine had elevated levels of tannins and anthocyanins compared to the control. CIELab color analysis reveals that the ACE wine was darker and more red than the control wine. The wines were significantly different in a sensory triangle test. There was no consensus as to which wine was preferred by participants.
Introduction
North Carolina red wines often struggle to have the concentration of anthocyanin and tannin that many other regions have. Accentuated Cut Edges (ACE) is a technique that may be beneficial for our region to maximize the extraction of the phenolics in our red wines. ACE mechanically cuts up grape skins thereby increasing the surface area of the edges and increasing the rate of extraction and is often achieved by the use of a machine such as the Della Tofola Maceration Accelerator. This machine separates the seeds from the crushed grapes and chops up the skins to roughly 10% of their original size. This process allows for accelerated extraction from the skins and not the seeds. A previous study using Marquette, a hybrid grape known for high anthocyanin and low tannin, showed an increase in color stability in wines made with ACE2.
Methods
Cabernet Sauvignon was hand-harvested on October 30, 2023. For both control and treatment, 0.9 tons of fruit was destemmed, crushed and pumped into temperature controlled stainless tanks. For the ACE treatment one bin (about 900 pounds) of fruit was pumped into tank and then blended with a commercial immersion blender (Tartle Kitchen, 500W) for 10 minutes until soupy and free flowing. Another bin of fruit (about 900 pounds) was crushed and added on top and then blended for 7 minutes until soupy and free flowing. Color Pro enzyme (80 ml/ton) was added before crushing. Wines were inoculated with CVRP yeast on the same day as harvest. The following day 2 g/L tartaric acid and 20 g/hL Powerlees Rouge was added. Both wines were chapitalized to 23 Brix. Wines were punched down twice daily for equal amounts of time until dryness. Both fermentations were dry on day 14 of maceration and were pressed separately on day 15. The press wine was kept separate for both lots and no longer used in this study. The free run wines were allowed to settle in tank for three days and then racked into neutral barrels of the same age. The wines were inoculated with VP41 malolactic bacteria. Upon completion of malolactic fermentation 80 ppm of SO2 was added. The wines were sampled after three months of barrel aging and the samples were sent to ETS Labs for phenolic and color analysis. Sensory analysis was performed on the samples by a panel of 62 wine industry professionals. Panelists were presented with a triangle test where there were three glasses of wine, two of them were the same and one was different.
Wines were presented blind with randomized three-digit codes on each. There were 6 tasting groups where the presentation order was different and the unique wine was balanced between the groups. The panelists were asked to identify which of the wines were different from the other two and then asked which wine they preferred.
Results
Starting chemistries of the juices were similar with the control having slightly higher Brix, pH and TA (Table 1). The increased rate of color extraction in the ACE treatment within the first hour was dramatic (Figure 1). The control wine had a higher pH and volatile acidity (Table 2). The ACE wine had slightly higher phenolic measures of catechin, tannin, monomeric anthocyanins, polymeric anthocyanins, and total anthocyanins (Table 3). ACE wine had higher absorbance at 420 nm and 520 nm indicating higher color intensity (Table 4). CIELab coordinates indicate that the ACE wine was darker (lower L*), slightly more purple (lower hue angle) and more intense in color (higher chroma) (Table 5). In the triangle test 34 of the 62 participants were able to distinguish which wine was different indicating the wines were significantly different. Of those that were able to distinguish the different wine 16 preferred the control and 14 preferred the ACE treatment.
Figure 1: Control (left) and ACE (right) Cabernet Sauvignon juice one hour after treatment.
References:
(1) Kang W, Bindon KA, Wang X, Muhlack RA, Smith PA, Niimi J, Bastian SEP. Chemical and Sensory Impacts of Accentuated Cut Edges (ACE) Grape Must Polyphenol Extraction Technique on Shiraz Wines. Foods. 2020 Jul 31;9(8):1027. doi: 10.3390/foods9081027. PMID: 32751842; PMCID: PMC7466200.
(2)Cheng Y, Savits JR, Watrelot AA. Effect of the Application Time of Accentuated Cut Edges (ACE) on Marquette Wine Phenolic Compounds. Molecules. 2022 Jan 15;27(2):542. doi: 10.3390/molecules27020542. PMID: 35056854; PMCID: PMC8779630.
References:
(1) Kang W, Bindon KA, Wang X, Muhlack RA, Smith PA, Niimi J, Bastian SEP. Chemical and Sensory Impacts of Accentuated Cut Edges (ACE) Grape Must Polyphenol Extraction Technique on Shiraz Wines. Foods. 2020 Jul 31;9(8):1027. doi: 10.3390/foods9081027. PMID: 32751842; PMCID: PMC7466200.
(2)Cheng Y, Savits JR, Watrelot AA. Effect of the Application Time of Accentuated Cut Edges (ACE) on Marquette Wine Phenolic Compounds. Molecules. 2022 Jan 15;27(2):542. doi: 10.3390/molecules27020542. PMID: 35056854; PMCID: PMC8779630.
