Tuesday, January 21, 2014

Sensory Evaluation - The Basics

Read previous sensory evaluation articles - The Language of Wine, Wine & Bullfighting.

Sensory evaluation is a part of every human's daily life. Love that smell when the sun comes out after it rains? How delicious that pizza is from the restaurant on the corner? Hate being stuck in traffic behind the trash collector? Sensory evaluation is all around us. For food and beverage makers, sensory evaluation is part of the job. Whether it's cheese, chocolate, cider, spirits, or wine, sensory evaluation is a key element in making sure the product turns out as intended.


To start, here are a few important factors to keep in mind when completing sensory evaluation:

Setting - It's lovely to sip champagne while sitting in the hot tub, relax on the beach drinking Chardonnay, or warming up around the campfire with a hearty Cab. That does not mean that these are good settings for proper sensory evaluation. Most wineries have a tasting room that offers a neutral setting for evaluating wine (I'm not referring to the one for customers but for winemakers). These rooms are typically white-walled with white benches (for wine color evaluation), void of outside scents (enclosed and well-ventilated, not in the middle of the cellar), temperature-controlled (somewhere around 20-22 C, or 68-72 F), and relatively void of distractions and noise.

This setting won't be available to everyone, particularly those outside of a production setting. In lieu of this, aim for a relatively neutral environment when tasting: not too hot or cold, void of overpowering fragrances, relatively ventilated, and preferably with minimal distractions.

Utensils - I'm not referring to the wine, but everything else. You obviously need some glasses, but which to choose? Studies have revealed that glass shape affects taster's perception, which has led to companies producing glass specific to varietals (for instance, Riedel produces pretty much every glass shape imaginable these days including those touted as varietal-specific). For sensory evaluation, tasters should use a standard tasting glass that is relatively-thin and clear (for visual assessment), narrower at the top and bottom than the middle (for concentrating aromas inside), sufficiently sloped sides and size to allow for vigorous swirling, and a stem that allows for proper handling. The ISO tasting glass has always been a favorite, but any regular tulip-shaped glass will do. During blind tastings, opaque glasses may be desired if visual inspection is not desired.

When many wines are to be poured set out at once, watch glasses can be used for cover as to minimize loss of volatile compounds, and for further concentration of aromas during evaluation. I have used other devices in a similar fashion when we lacked watch glasses; I had a boss that swore that petri dishes worked better as they fully covered and enclosed the top of the glass.

Decanters can serve two purposes; sediment removal and aeration. Decanters are similar to carafes, and come in a variety of shapes and sizes (just like glassware today); the same theory of narrow opening with a wine center-point still in play. Unfiltered and older wines may contain high amounts of sediments, so decanting is useful for removing the clear wine from the bottle and leaving the sediment behind. Decanters can also be used for aeration of wine, though this topic is subject to debate. The theory is that using a decanter creates a similar situation to swirling wine in a glass, promoting aeration and releasing more aroma compounds. Decanters are also said to help soften tannins of powerful wines such as Cabernet Sauvignon and younger wines. Of course, they can also allow the service of anonymous wine if desired.

A Spitton or a sink for spitting post-tasting is always ideal, particularly when many samples are to be tasted. A person's sensory skills will steadily go downhill if not, and even the most skilled wine tasters cannot evaluate wines nearly as well drunk as sober. I have worked in wineries were ferment management required tasting over 100 samples in the span of an hour, and you could easily end up with a buzz despite spitting.

Paper and a pencil, whether it's a standard issued sheet for the specific tasting event or just a pad will help organize and verbalize thoughts. This not only helps tasters with remembering which wines tasted, but also the characteristics associated with each at the time.

Wine Temperature - When evaluating wines in a production setting (or any technical setting), the wine should be at a standard temperature between 14-16° C (58-61° F). Temperature variation can make a big difference in sensory perception: muting, masking, enhancing, etc. During more informal tastings, temperatures can be adjusted as per usual: crisp whites and sparkling wines between 5-10° C (40-50° F), fuller-bodied whites and lighter-bodied reds between 10-15° C (50-60° F), and full-bodied reds and dessert wines between 15-18° C (60-65° F).

Prepared Tasters - Tasters should have a fresh palate, and not 'just brushed my teeth' fresh. Essentially, tasters should avoid anything that would intrude on their senses. It's recommended to avoid things such as spicy foods, chocolates, mints, and cigarettes prior to tasting sessions. Tasters should not show up sick (having the flu is obviously going to effect sensory perception), or drunk (not only does it effect your palate, but it's just not a good look). The use of perfumes and colognes should be minimized and not too strong (this doesn't mean don't use them at all as body odor isn't pleasant either!).

Taste Properly  - There really isn't one correct way to evaluate wines. Depending on the type of evaluation being conducted, there are several different approaches.

The techniques and analysis of sensory evaluation will be discussed in following posts, so check back.

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