Brix
°Brix is a useful measurement used to approximate sugar concentration in grapes and fermenting wine. As a percentage by weight (% w/w), one degree brix represents 1 gram of sucrose in 100 grams of water. Because sugar only accounts for 90-95% of dissolved solids in grapes, it is best described as “apparent sugars” (Waterhouse et al., 2024).
In the vineyard, °Brix is valuable for estimating the amount of alcohol that will result after fermentation with a common conversion factor between 0.55 to 0.64. Interestingly, while heat events increase °Brix in berries through dehydration, they generally decrease the dry weight of sugar in each berry shifting clusters from being nutrient sinks to nutrient sources. This is one reason why measuring the grams per liter of glucose and fructose (aka berry sugar loading) is a valuable tool for evaluating vine metabolism, and why both parameters are included in our Grape/Juice panel.
Similarly, °Brix is used to track the progression of fermenting must in the winery. °Brix values less than 0 are indicative of near completion, and Glucose/Fructose measurement can be used to characterize dryness (below 2 g/L). Interestingly, °Brix can also be used to predict stuck fermentations using the Boulton Model that was created in the 1980s. The rate of Brix change is representative of the active fermenting yeast population. By juxtaposing the speed of fermenation with the fermentation temperature, the Boulton Model can reasonably predict whether or not a fermentation with finish. As you can see in the graph below, the model predicted a struck fermentation until the winery increased the fermentation temperature allowing the wine to achieve 0 °Brix.
Figure 1. The Boulton Model Prediction using pressure transducers for continuous °Brix in a commercial white wine fermentation. (The Future of Winemaking: Honoring the Vision of Professor Roger Boulton, 2022).
While °Brix measurement is ubiquitous across grape growing and winemaking in the United States, understanding its relationship to environmental factors like temperature and other parameters like Glucose and Fructose can help producers make the best decisions for their desired outcome.
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FAQs
Frequently Asked Questions
Sample
- Use a 50 mL centrifuge tube with a Bound Sample Label attached.
- Sample your wine in a way that is most representative of the entire lot (i.e. practice flushing your sample valve, collecting after movements like pumpovers, stirring your barrel, etc.).
Label
- Label each sample appropriately with your Client ID, Sample Date, and Sample ID. Samples for Phenolics analysis also require a Crush Date, Varietal, and Appellation. The analysis cannot be performed without the applicable information for each sample.
- Mark the sample type. This is critical for applying the appropriate model for each sample. ”Juice” applies to grapes and juice samples before fermentation. ”Must” applies to samples undergoing primary or secondary fermentation. ”Wine” applies to samples after fermentation and includes SO2 analysis.
- In addition to sample type, you must also select the panel and/or the individual analyses for each sample. For panels, select “Standard” for our juice, must, and wine panels, or select “Phenolics” for our phenolics panel. These panels may be selected individually or in conjunction with one another. For individual analyses, write each parameter at the bottom of the label. A list of individual analyses is on our ANALYSES page.
Beginning the week of August 26th, 2024, clients will be able to submit samples directly to our lab, via the mail, or arrange for pickup at select locations.
To arrange for pickup, clients must be located near Santa Barbara, Goleta, Buellton, or Lompoc and notify us by 10 am for same-day retrieval. Please contact us for more information.
- We strive to provide same-day results for our clients and guarantee turnaround within 24 hours of sample receipt.
- Those that are not analyzed same-day are refrigerated overnight and analyzed first thing the next morning.
- Results are delivered via email in PDF format.
- Our invoices are sent via email and are due upon receipt.
- Your payment is securely processed through Bound’s website. Click the link in your email to be directed to our payment page.
To ensure their stability, we ask our clients either freeze or boil their juice / fermenting wine samples before shipment. Please note that boiling or freezing your samples may influence your results and we cannot guarantee their validity. Please contact Bound with any additional questions about sample preparation before shipment. We recommend expedited same-day to one-day shipping with a tracking number included.
Frozen
Samples can be placed in a freezer 24-hours in advance and shipped with an ice pack. Do not over-fill the polypropylene tubes or use glass containers as the frozen liquid will expand and could pose a safety concern. Freezing samples is a better alternative to boiling when analyzing compounds like ethanol, volatile acidity, free sulfur, and phenolics. Label each sample as "FROZEN".
Boiled
Samples can be boiled in their 50 mL polypropylene centrifuge tubes with a loosely fitted cap on top. Polypropylene tubes can be boiled up to 10 minutes, but be sure not to over boil as exposure to high temperatures can change your results. Label each sample as "BOILED".
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