How to Achieve Better Quality Control with Less Effort

A small winery in central California found a way to speed up managing the daily workload without compromising on the quality of analyses and cultivation. Portable instrumentation helps cope with the daily inspection of the checkpoints and allows for continuous monitoring of the progressing development of the wine’s characteristics.

The delta breeze enhances the grape quality

In the small city of Lodi in the northern part of California’s Central Valley, around 65 miles east of San Francisco Bay, the Bear Creek Winery (see Fig. 1) cultivates its fine assortment of wines.

Bear Creek Winery
Fig. 1. Bear Creek’s welcoming sign in Lodi, CA

The area around Lodi is blessed with a very steady growing season. Although it experiences some heat spikes, conditions are excellent for growing wine grapes because of a phenomenon called the “delta breeze”. As the warm air rises in the evening, cool air is drawn in from San Francisco Bay and makes the Lodi region experience a very large difference in temperature between day and night. The diurnal change is excellent for grape growing and that is what makes the Lodi region stand apart.

Proven growing area and new grape varieties liaise successfully

Bear Creek Winery was founded in 1934 and has been owned by the Kautz family since 1997. John and Gail Kautz were instrumental in opening up certain grape varieties in Lodi. They were the first to plant Chardonnay and Cabernet Sauvignon and they are also the largest growers of Cabernet Franc and Symphony. Despite the Kautz’ success story Bear Creek Winery still remains a family organization, setting an example of how upholding tradition and moving with the times can be combined.

At Bear Creek Winery they grow between 40 and 45 thousand tons of grapes a year that are turned into red wine varieties such as Cabernet Sauvignon, Merlot, Syrah, but also more unusual varieties that are mostly used for blending, such as Sousão or Tannat, and white and blush wines such as Chardonnay, Sauvignon Blanc, and a Shiraz/Cabernet Sauvignon rosé. The white and rosé wines are primarily processed in an atmosphere where oxygen is excluded at all times by driving the air out with CO2. “This provides a reductive style that the Bear Creek Winery takes a pride in,” says Michael Borboa, Export Winemaker, who studied at Fresno State University. “The reductive atmosphere can be seen by the green color of the juice because the oxidative browning that causes the wine to turn amber is minimized,” he explains.

Profound analyses made easy for premium quality wines

At Bear Creek Winery comprehensive quality control is performed throughout the entire production process. The final products in particular undergo close examinations of residual sugar, volatile acids and malic acid. The alcohol content is measured using an Alcolyzer alcohol meter by Anton Paar which is based on a near-infrared method (see Fig. 2). SO2 and O2 determinations are also on the agenda as well as the occasional test for filterability.

Anton Paar Alcolyzer
Fig. 2. Experienced staff measures the alcohol content in the laboratory

Analyses are not only performed during fermentation and on the finished wine; they already start with the grapes. “We sample each load of grapes right away so we can immediately decide whether any additions are needed. These adjustments may include tartaric acid, SO2, or pectolytic enzymes for white juice or color extraction enzymes for red juice,” explains Michael Borboa. “Our winemakers evaluate each individual lot of juice and adjust accordingly to ensure a healthy fermentation.”

In recent years, Bear Creek Winery has found an even better way to manage the daily workload by using a portable density meter for quality checks. This reduces the time spent checking tanks and is much easier to use than a hydrometer.

Modern instrumentation makes the workload easier to handle

Quality control during fermentation in the wine tanks plays a very big role at Bear Creek Winery. Here, a small portable density meter, a DMA 35 by Anton Paar, proved to be the ideal companion that makes daily work much easier. Before acquiring a DMA 35, the operators had to carry a basket containing a hydrometer with the required accessories up to the top of the tanks to perform the measurements. This tedious work is now a thing of the past: The DMA 35 density meter has made the hydrometer obsolete. Now, quality control personnel do not even need a clipboard and pen because the measuring result is automatically recorded by the DMA 35 density meter.

At some stages there are between 50 and 100 fermenters that have to be checked twice a day. While it used to be common practice to spend maybe 10 or 15 minutes for one tank sample, nowadays with a DMA 35 a check takes only 3 to 5 minutes per tank. This saves a lot of time and effort and allows the winemaker to take action faster if needed to ensure that the health of the wine is maintained.

Radio Frequency Identification avoids sample mix-up

Radio-frequency identification (RFID) allows wireless data transfer between tags and devices with an integrated RFID interface. RFID tags are commonly used for identification purposes in many industries and have also found their way into wineries due to their ability to uniquely link the measured characteristics of a certain product, for example a fermenting wine, to the location where the sample was taken – usually a barrel or tank, where the tag is attached.

The DMA 35 version “Tag&Log” is equipped with an RFID interface with a reading range of about 2 cm. Installation of the tag is an easy and straightforward task as can be seen in Fig. 3, Steps 1 and 2. The instrument provides the ability to program an RFID tag with a sample name and also method settings for the measurement of that very sample. For the day-to-day routine, the tag is scanned before the measurement (compare Fig. 3, Step 3) in only one second. If required, settings can also be erased and programmed anew. Measured data are stored in the DMA 35 including the identification information. Wireless data transfer to a computer or printer is done with an infrared interface (IrDA).

Step 1
An RFID tag is programmed with a specific sample name.
Step 2
The tag is attached to a barrel or tank. Programming the tag is done with the DMA 35 directly, no additional gear is required.
Step 3
From now on the tag is ready to identify samples for the day-to-day routine.

Fig. 3.
Installation and daily use of a DMA 35 RFID tag

Quick sample identification at numerous measuring points within a winery means enormous time savings. The density measurement with DMA 35 takes less than a minute, and the instrument reads an RFID tag and identifies the name of a sample in only one second.

Immediate information by density measurement at many stages in the winery

Portable density meters not only come in handy at the tanks for determining the sugar concentration in the grape juice and the decrease of sugar during fermentation, they are also used for checking the sugar content and ripeness of the berries. Density measurement is also employed to check on the right concentration of dissolved SO2 to be added as a stabilizing agent to the wine. Another positive aspect of the DMA 35 density meter is the calculation of filling volumes from the weight before shipping the wine to the customer.

The handheld DMA 35 density meter has been used for the last three seasons at the Bear Creek Winery for analyses on tanks to monitor the development of the wine and keep it on the right track (see Fig. 4). “The biggest advantage of the DMA 35 is that it is portable and very accurate at the same time,” reports Michael Borboa. “These features make it ideally suited for taking it around to the tanks.”

Dma 35 RFID reading
Fig. 4. Reading an RFID tag on the tank with the portable DMA 35 density meter

Trends in wine consumption

Currently Bear Creek Winery is experiencing a distinct trend for sweeter wines. As Michael Borboa explains, “Nowadays, younger drinkers seem to prefer sweeter wines. There has been a tendency in the last few years for wine that has been traditionally dry to be produced sweeter.” Confirming this trend, Borboa mentions the increasing popularity of Muscat or Moscato in the United States. Young drinkers are choosing this floral, semi-sweet wine and making it very fashionable.

Another phenomenon witnessed by Borboa is the rise in popularity of the Lodi region. “Over the past couple of decades Lodi has grown into a first-class wine-growing region. There are now more than 75 wineries in the Lodi American Viticultural Area and wine enthusiasts fully recognize their world-class products. With the Kautz family’s continued efforts to advance and improve grape-growing and winemaking in Northern California this upwards trend is sure to carry on.”

The use of new technology, such as DMA 35 with RFID interface, has made Bear Creek more efficient and more progressive. The scene is set for the continued success of Bear Creek’s remarkable high-quality wines. Even though Michael Borboa has recently moved on to new responsibilities outside of Bear Creek Winery, he still takes to using Anton Paar instrumentation at his new job as Senior Winemaker.

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