pTAN:IRPs
The Protein-Precipitable Tannins to Iron-Reactive Phenolics ratio (pTAN:IRP) is a useful metric for understanding extraction in skin-macerated wines. Iron-Reactive Phenolics extract readily from grape pulp whereas Protein-Precipitable Tannins require alcohol, temperature, and movements to extract from the skins and seeds. Because of this, high production wines tend to have lower ratios whereas reserve-tier wines generally have higher ratios. pTAN generally account for 50-55% of extractable IRPs in skin-macerated wines. This ratio will fluctuate depending on fruit quality, most notably decreasing with hotter climates.
Protein-Precipitable Tannins: Iron-Reactive Phenolics (pTAN:IRPs)
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<0.3 is low-efficiency extraction typical of shorter macerations and larger production volumes.
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3-0.4 is a moderately efficient extraction typical of middle-tier wines.
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4-0.5 is a highly efficient extraction typical of premium and reserve wines.
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>0.5 is heavily extracted typical of powerful wines.
For winemakers, these ratios are particularly useful for monitoring adherence to protocols and understanding the performance of vineyards across multiple vintages. We generally don’t place value between higher or lower ratios as a sign of quality, rather, we focus on pTAN:IRP as an indicator of extraction. Lower ratios benefit more delicate wine styles whereas high ratios benefit more concentrated wine styles. We can use the following variables to steer the type of extraction we desire based on the qualities of our fruit.
To learn more about the pTAN:IRPs ratio and how it applies to winemaking, become a Bound member.
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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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