Triage for a Basic Wine/Grape Lab
Equipment and other choices for conducting essential daily analyses
My mantra for all wine and grape production has always been: The more you know about your grapes or wines, the better grapes you will grow and the better wine you will make. All wineries, no matter how big or how small, need to have at least a minimal laboratory set up to provide basic test results at the winery. Whether initially setting up your wine/grape laboratory or reviewing your current laboratory and its capabilities, it is important to have a plan for the role a laboratory plays in delivering high-quality fruit or making high-quality wine.
This article, the first in a two-part series, will review the essential equipment you will need and the choices available for a minimum wine laboratory. While a winery must evaluate the cost benefit of these purchases, in many cases spending a bit more initially will save many dollars later on and, along the way, help make better wine. In creating the essential laboratory, the approach is to obtain the minimum set of equipment to be able to conduct those analyses that are absolutely essential for a winery’s day-to-day operation.
Every winery should have some reference works, and one of the most important is “Wine Analysis and Production” by Bruce Zoecklein, Barry Gump and Ken Fugelsang. A new edition is about to be published, but the previous editions are still valuable. Other useful reference works include Murli Dharmadhikari’s “Laboratory Manual for Wine and Must Analysis,” Patrick Iland’s “Chemical Analysis of Wine and Grapes,” and “Wine Microbiology” by Ken Fugelsang. There are many other good books published on this topic, but these are books that I have used most frequently.
Laboratory location and design
When designing the winery building or planting the vineyard, remember to think about your laboratory. Resist the temptation to squeeze the lab into a corner so you don’t have to have a separate room, as this is a sure recipe for the laboratory to be more of a nuisance than an asset. The laboratory is where many of the most important decisions in winemaking occur, as well as other important tasks such as new product development and final blending trials. While there are laboratory tasks that require separation from the main winery or vineyard areas, the lab must be convenient to those areas.
A laboratory needs its own dedicated space for functional reasons. It has ventilation requirements similar to those of the bottling room, as these two rooms function best when drawing air filtered from the outside into the winery building. Airflow should be separated either via sanitary filters or using an air-handling system completely separate from the main winery ventilation system. This is important both to reduce contamination in the bottling room as well as laboratory contamination for quality-control microbiological tests.
Another important piece of equipment to install in both a laboratory and the bottling room is an Airocide unit. These air purifiers significantly reduce the possibility of microorganism contamination (see “Essential Laboratory Analyses: Monitoring Winery Sanitation” in the November-December 2006 issue of Wine East and “Wineries Achieve Control of Mold Growth” in the June 2013 issue of Wines & Vines.)
The laboratory needs large sinks with high faucets and plenty of hot and cold water that is softened, either a garbage disposal or sump that can take small amounts of diatomaceous earth, grapes and/or fruit left over from tests; vacuum systems; nitrogen gas; compressed air and access to the winery refrigeration system. There must be enough space so that multiple analytical tasks can be set up easily. Lack of space to set up an analysis should not be a n excuse to not run the tests. In addition, future expansion of the lab should be considered: It is cheaper to make the room somewhat bigger initially and use that extra space for a non-conflicting function to justify the larger space before the laboratory expansion occurs.
The laboratory must have sufficient cabinetry for glassware, equipment and chemical storage. Some wall space is necessary for equipment that needs support stands or lab frames. Lab benches are a critical necessity. While it can be quite expensive to install chemical-resistant lab benches, there are alternatives that are less expensive and easy to install. Consider stainless steel surfaces, as in a restaurant. Formica is another choice, but it is not as chemical-resistant as stainless steel and can be stained by spills of strong chemicals or darkly colored red wine. Install a floor drain in the laboratory to take care of the accident that is waiting to happen.
Lighting is another important consideration. Not only is it necessary to have good light, it must be the correct quality of light. Daylight quality is the standard—not fluorescent or warm light tones. A sufficient amount of countertop and table area should be available that has a white surface in order to evaluate wines against an appropriate background.
From a safety standpoint, a lab should have either an eyewash emergency kit mounted on the wall near an exit door or, if funds are available, an emergency shower stand. This device allows a full-flow shower to drench strong acid or base compounds that have been accidently spilled, so a chemical burn would not penetrate clothing and burn skin.
Minimum analytical equipment requirements
Any reference book will give a long list of analyses done in the wine and grape industry. This article will be a discussion of the cost benefit of different methods of analysis, not a review of how to perform these analyses. With the understanding of the various ways an analysis can be performed, a reasoned decision can be made about whether to spend more for one method over another and the return that the choice will provide.
When starting a wine laboratory, an initial response is often to buy specific equipment for a given analysis. It is better to identify the necessary support equipment and then purchase that equipment as part of the basic setup. If you have a working laboratory, review the status of your equipment. In reviewing your laboratory procedures, look at the number of any tests that you would typically perform in a day or session. That number should be no less than three for any test (because you can draw a straight line through any two points) but should always be an odd number.
Support equipment includes beakers, flasks, filter apparatus, vacuum systems, stir plates, hot plates and much more. Some of this equipment is used by virtually every test conducted in the laboratory and will not be an inexpensive part of the whole laboratory setup. A suggestion list of the minimum supplies that all laboratories will need is posted here.
There are several laboratory equipment companies (including VWR Scientific, Thomas Scientific, Cynmar Corp. and Thermo Fisher Scientific) that supply this equipment as well as much of the equipment mentioned below. Compare the prices for various items, since there is variation in the pricing structures between companies.
Basic lab analyses
If you are starting a new winery, get the best equipment you can afford for each of the tests. The table on page 76 shows three levels of analyses for a basic wine laboratory. The five tests discussed below are some of the most fundamental for your laboratory, because these evaluations will allow you to protect your wine from future damage, detect a problem and correct it, or create the products that determine your winery’s success.
In a vineyard or winery, measuring soluble solids is one of the first analytical steps used to determine the harvest date. Two types of instruments are required: one for measuring juice soluble solids and one for wine-soluble solids. A hydrometer can measure both juice and wine, but a refractometer should only be used for juice. Alcohol has both a different refractive index and a different specific gravity than water, and its presence will introduce significant errors in your readings when a refractometer is used to measure soluble solids.
While a refractometer is used prior to beginning fermentation, the hydrometer is used during both harvest and fermentation. Be sure you have enough tubes to allow the hydrometer to sink its full length. A lab should have at least one that will cover the range of grape soluble solids, typically from 0° to 30° Brix. This hydrometer is not expensive. If you need one for high-Brix grapes such as late-harvest, limited-range hydrometers, such as one for 30° to 45°Brix, are available. Most importantly, be sure you have a +5° to -5° Brix hydrometer. This type is not as inexpensive as the 0° to 30°, but it is highly useful to determine accurately when fermentation has ended.
These fragile devices can be protected by a cover made out of PVC pipe. Glue a cap on one end of the correct diameter pipe and place a piece of foam in the tube. Then put another cap on the other end. It won’t protect a hydrometer that is dropped, but it will protect against something tipping onto it.
Every laboratory should have glassware to run the manual wet chemistry tests such as the burettes used for total acidity tests. However, this equipment is not the best way to run routine total acidity tests. For a complete total acidity analysis you will need
a hot plate or microwave, burette stand, holder and burette, and
a pH meter.
It will take several minutes for the first test, but after that, you can run several tests fairly quickly. Even if you plan to run more tests later that day, do not leave reagent in the burette because it will start to evaporate and could alter your results. Many people put this reagent back into their stock bottle because they don’t want to waste it, and because of the time it takes to make and standardize the stock and working solutions. However, it does not take much to alter the standardized solutions, and then errors can occur.
It is preferable to get one of the simple titrators made by Hanna Instruments, which allows titrating from standardized solutions. Setup time is reduced, you can run one or a dozen tests, and it makes little difference in the overall time to run one test from another. It’s easy to clean up and maintain. Over the long haul, it is more cost effective that the manual method, and because it is easy, everyone has the incentive to run the test.
There are many fine pH instruments on the market. However, this is one case where you need to spend some money, as the cost is almost always directly related to the precision and accuracy of the output. Just because some manufacturers claim to have a certain level of accuracy doesn’t mean they will be able to make that measurement for long or repeatedly.
The ideal lab would have a bench measuring meter and a portable one to take to the bin/tank and measure directly from the container. If you must make a choice, get the bench model. It will serve you better in the long run since it will be less likely to have its probe crushed or encounter some calamity such as being run over by a forklift.
My personal favorite is the Hanna bench model that is designed for wineries. It has a standardized set point for a 3.0 pH buffer as well as the other standards. In this way the meter is standardized on the exact range for wine.
Thermo Fisher Scientific, Mettler Toledo, Metrohm USA, Orion, VWR Scientific, Thomas Scientific, Cynmar, Milwaukee Instruments, Cole-Parmer Instrument and Denver Instrument all have good instruments as well. A good, solid unit that will last many years will cost $500-$800.
From a regulatory standpoint, this is one of the most important analyses a winery performs. The tax on wine is based on the amount of alcohol it contains, and your analysis determines that level. With global warming, more wines are exceeding the magic 14% alcohol level where higher wine taxes are assessed. The analytical error for dry wines using an ebulliometer accumulates based on several factors: air pressure (+/- 0.5%), thermometer reading (+/- 0.04%), conversion scale (+/- 0.02%).
The closer a winery’s wines are to 14%, the better the instrumentation needed so that the winery doesn’t pay any more taxes than required. Dujardin de Salleron of France makes the vast majority of the units sold in this country. Other companies include GAB Sistematica Analitica of Spain and EON Trading LLC of Bulgaria.
There are two types of ebulliometer. The standard version that is heated with an alcohol burner has been manufactured for decades. The setup time to establish the current boiling point of water with this instrument is 15 minutes, and it takes an additional 15 minutes for each sample.
The new winery or the wine laboratory wishing to improve throughput should seriously consider the electronically heated version of this unit. The time saved in number of analyses per hour can quickly cover the extra cost of the electronic heating. The time saved for one analysis, including the barometric set point, is 20 minutes, plus a savings of 10 minutes for each sample after the first one. Based on an average of four wine samples analyzed simultaneously, the daily savings is 40 minutes (or more if the weather changes while testing and another air-pressure sample is required). At this rate, it doesn’t take long to save $500 in labor costs and pay for the better instrument.
A completely digital version is also available. While providing more accuracy in data gathering, it is considerably more expensive and would take much longer to get the return on investment.
Sulfur dioxide is another test where wet chemistry using glassware can provide answers. Good results can be obtained using either the older Ripper method or the newer aeration oxidation method of analysis. With glassware, running the Ripper method is somewhat problematic with red wines, since the analysis relies on a color change to obtain the endpoint of the analysis. That was the genesis for the development of the aeration-oxidation method that separates the color of the wine from the titration of the SO2.
Regardless of the method used, each SO2 test takes approximately 20 minutes to complete. If you have dozens of tanks and/or barrels, that is a serious commitment of laboratory time just for SO2 analyses. However, the mini-titrator by Hanna reduces the time for an individual analysis by 75%. While based on the Ripper chemistry, this instrument has lowered the inherent error of red wine analysis by incorporating an ORP probe as the sensing device, which takes the judgment out of the endpoint determination. Aeration oxidation remains the gold standard for SO2 analysis, but the difference is so slight that it is not significant, especially when considering the natural variability of SO2 in any wine.
Sample preparation and defect detection
Simple pipettes can be used to create lab sample wines, but in order to make accurate samples you must use rather large quantities of wine for each sample to evaluate. To avoid that prospect, use an analytical balance to weigh out milligram amounts of amendments or pipette microliters of a fining agent, copper treatment for H2S or other materials accurately. A balance will cost between $1,100 and $1,500.
Look carefully at the equipment list and get good quality auto-pipettes. These pipettes are about $200 each plus appropriate tips. You are paying for precision and flexibility; the best recommendation is to get one 20 to 200µL, one 100 to 1,000µL, and either a 1ml to 5ml or 1-2ml to 10ml auto pipettes. This range of pipettes will allow preparation of 100ml samples of wine that can be accurately scaled from the lab to production levels. An analytical balance accurate to +/- 1mg will allow for additions to 100ml of wine that also will scale. Couple these tools with some simple lab filtration and you will be able to duplicate a finished wine in 100ml increments.
The next article
The second part of this series will explore more advanced equipment that, for a few dollars, will improve your understanding of your wine and its health, and significantly improve its quality.
Dr. Richard Carey is president of Vitis Wine Center and winemaker for Tamanend Winery in Lancaster, Pa. He has written numerous articles on new technologies for the grape and wine industry as well as a series of articles on laboratory analyses in Wine East magazine.
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