Is Your Glass Half Empty? Or Half Full?: How Distractions Influence the Amount of Wine Poured

When you are pouring yourself a glass of wine, are you aware of how much you are actually pouring into your glass?  Do you think you’re pouring yourself the standard serving? Or does the amount in your glass fluctuate depending upon a variety of cues (such as glass size, music, lighting, general ambiance, etc)?  According to some research, a relatively large number of people are not aware of what is a standard serving of alcohol.  A standard serving of alcohol is 14g (18mL), which if you do the math is equivalent to 12 ounces of beer (at 5% alcohol/vol), 5 ounces of wine (at 12% alcohol/vol), or 1.5 ounces of spirits (at 40% alcohol/vol).

When you order a drink from a restaurant or bar, for the most part you’re probably getting an accurate (or close to accurate) serving.  However, when you’re at home or someplace else where you can complete control over how much goes into your glass, you’re much more likely to pour more than a standard serving.  In reality, there is a lot of variation in

Photo by Deutsche Fotothek‎ [CC-BY-SA-3.0-de (], via Wikimedia Commons

Photo by Deutsche Fotothek‎ [CC-BY-SA-3.0-de (], via Wikimedia Commons

terms of alcohol content for any one beverage: some beers can be upwards of 10 or 11% alcohol, and wines will vary anywhere between 9-10% to 18%.  Technically, you would need to pour either more or less, in order to get the appropriate standard serving, but in real life, that really doesn’t happen often.  I know from my experience, unless I’m drinking a fortified wine, I tend to pour the same amount of wine in my glass regardless of what the alcohol content of that bottle was.

According to many studies, distractions in the environment tend to decrease our ability to carefully monitor our consumption.  One example that was given in the article presented today was that of plate sizes.  When presented with larger plates, subjects ate much more food than when presented with smaller plates.  In this case, the size of the plate was the distraction.  Changing plate sizes made it more difficult to determine what a serving size of food should be, so the subjects automatically filled it as much as would fit.  It’s possible that this same concept could be used in a wine-pouring setting.  Factors like glass size, shape, or color could distract the pourer enough such that he or she is not aware that they are pouring too much (or too little).

One hypothesis, based on the aforementioned knowledge, was that study subjects will pour greater amounts of wine into a large wine glass compared with a standard sized wine glass.

A second hypothesis, stemming from the first, was that study subjects will pour greater amounts of wine into a wide wine glass compared with a standard width wine glass.  This hypothesis stems from research that has shown that consumers will tend to focus more on glass height rather than glass width in determining how much they are pouring.

Other studies related to this type of behavior found that when presented with a table setting, either large or small, it triggered a signal to participants that food was nearby, and so they became hungry.  The authors of this study thought that perhaps the presence of a table setting would elicit a sort of “meal time” response, thereby perhaps when presented with a table setting, study subjects will pour a greater amount of wine as if in a dinner-type setting.

A fourth hypothesis stems from research that has found that when a consumer is faced with the prospect of increased effort, consumption levels decrease.  In other words, when there’s more work to do to get the reward, they would rather not try at all.  To this end, it was hypothesized that study subjects would pour more wine if they were holding the glasses than if the glasses were sitting on the table.  If they are already holding the glass, it’s less work to the final goal (wine) than if they had to pour first, then pick up the glass.

The final test in this study was to examine the concept of color contrast and quantity of wine poured.  Studies have shown that a high color contrast between the plate and the food resulted in a decreased amount of food consumed, while a low color contrast between the plate and the food resulted in an increase in the amount of food consumed.  As a result of this work, the authors of this study hypothesized that study subjects will pour more wine into a glass that has low color contrast to the wine going into it (i.e. light colored glass and white wine), while they would pour less into a glass that has a high color contrast to the wine going into it (i.e. light colored glass and red wine).


Study subjects were not made aware of possible pouring biases until after the experiment was complete, thus avoiding any possible biases due to cognizant pouring adjustments.

Photo By Kevin Ho (Flickr: KSHO_20101030_14-40-54) [CC-BY-SA-2.0 (], via Wikimedia Commons

Photo By Kevin Ho (Flickr: KSHO_20101030_14-40-54) [CC-BY-SA-2.0 (], via Wikimedia Commons

73 students of legal drinking age from an American university participated in this study (46 women and 27 men), with the average age of the group working out to be 29.1 years.  Subjects must have consumed at least one glass of wine a week in order to participate in this study.

Subjects were asked to pour themselves as much wine as they would for a single serving, and were asked to complete this task for 7 different scenarios (504 total pours).  At each station, there was a scale such that the amount of wine in the glass after each pour could be calculated.

The different scenarios included: glasses of different sizes and shapes, small and large table settings, no table setting, holding the glass in the hands while pouring, and finally keeping the glass on the table while pouring.

After the pouring segment, subjects were asked to complete questionnaires that measured the environmental influence of pouring (i.e. how each subject thought the different scenarios may or may not have changed the size of their pours).


  • Glass size and place setting (large or small) were NOT significant.
    • This means that the amount of wine poured did not differ between different glass sizes or whether or not there were large or small place settings present.
  • Glass width, pouring position (i.e. holding or on table), and color of the glass (i.e. color contrast) were statistically significant.
    • Subjects poured 11.9% more wine into a wide glass than a standard sized glass.
    • Holding the glass resulted in a 12.2% increase in the amount of wine poured compared to when the glass was sitting on the table.
    • 9.2% more wine was poured when a white wine was being poured into a standard clear glass than red wine being poured into the same colored glass.
  • Post-experimental questionnaires confirmed that subjects were aware that they may be pouring more wine into glasses of various scenarios.
    • In fact, the subjects were accurate in describing which scenarios they thought they might be pouring more wine and which scenario they actually DID pour more wine.


Yes, there was a lot of build-up to a relatively short results section, but alas, sometimes you need a lot of background in order to understand why certain hypotheses are chosen and the reasons why they may or may not hold true.

I found this study interesting in that it confirmed to me some of the suspicions I had about different pouring scenarios, and I was able to learn some things about scenarios I didn’t realize would be important.  For me, the most obvious result based on previous experience was the significant result found with the differing glass widths.  Pouring wine into a wide glass resulted in significantly more wine being poured into it than into a standard sized wine glass.  When you have a wide wine glass, a standard pour would have a relatively low height factor.  Many people probably look at that and say “hey, there’s barely anything in here”, because we tend to think more in the vertical than in the horizontal when considering volume (studies have shown this).

I thought the holding the glass versus setting the glass on the table result was interesting.  Are we that lazy that simply requiring us to pour then pick up the glass will deter us from pouring more?  Perhaps it has something to do with angles and balance: maybe when the subjects were holding the glass, they were holding them at a slight angle, thereby giving the appearance of less wine in the glass compared with setting on the table when the wine surface is level with the table and thus obvious how much has been poured.  Is it something this simple? Or are there some other more complicated mechanisms at work here?

A few things leave me taking all of the results with a grain of salt, however.  First of all, the sample was relatively small and only represented a certain subset of the community (i.e. 73 graduate and undergraduate students with an average age of

Photo By Fabio Ingrosso (Flickr: Vinitaly, bottiglia di vino) [CC-BY-2.0 (], via Wikimedia Commons

Photo By Fabio Ingrosso (Flickr: Vinitaly, bottiglia di vino) [CC-BY-2.0 (], via Wikimedia Commons

29.1).  Are these results representative of the population as a whole?  Would someone with say a high school education or less from a non-university town show similar results?  Or would we see differences there?

Another factor that I think is worth looking into is what happens when you’ve consumed the first glass and are going to pour the second glass?  Certainly the alcohol factor will be significant here, and I would expect that the consumer would pour more in the second glass due to the inebriating effect of the alcohol.  This might sound like a “duh” situation, but nonetheless, sometimes what’s seemingly very basic can, in turn, be very interesting or lead to further questions that could have important social or physiological relevance.

Overall, I thought this was an interesting study, though I would certainly consider it more pilot-level than one that can be generalized to a larger population.  I’d like to see this type of study repeated on a wider scale, and perhaps include other potentially important environmental cues such as music, lighting, or the company of friends, as it’s well known that these types of distractions affect ones perception of quality and desire to purchase than sitting in a quiet room all by oneself pouring a single glass of wine.

I’d love to hear what you all think of this study!  What other tests would you like to see next?  What did the authors leave out that you feel would have been an important thing to test?  Please feel free to leave these and any other comments you may have in the comment section!

Source: Walker, D., Smarandescu, L., and Wansink, B. 2013. Half full or empty: cues that lead wine drinkers to unintentionally overpour. Substance Use & Misuse In Press. Available early online DOI: 10.3109/10826084.2013.832327


13 comments for “Is Your Glass Half Empty? Or Half Full?: How Distractions Influence the Amount of Wine Poured

  1. Hal Hinkle
    September 24, 2013 at 10:16 am

    I’m familiar with Wanksink and other’s work on how setting (mostly plate size) impacts quantity consumed. My take is less that the setting factors are a DISTRACTION (that wasn’t Brian W’s thesis in his earlier work) and more that for some consumables we carry expectational TEMPLATES. Also we need to distinguish between consumption size and serving size.

    You do great work, please keep it up.

    • Becca
      September 24, 2013 at 12:01 pm

      Hi Hal! Thank you for your great comments! You’re right, “distractions” may not be the correct word to capture all that is going on here. I would think on some level there is a bit of distraction, but what is really happening is likely more on a subconscious level.

      Wonderful input! Thank you!

  2. Bob Henry
    September 24, 2013 at 9:16 pm


    You and your blog readers should read this article.

    ~~ Bob

    Excerpt from The Wall Street Journal “Personal Journal” Section
    (May 1, 2007, Page D1):

    “The Accidental Binge Drinker: How Much We Really Pour”


    By Tara Parker-Pope
    “Health Journal” Column

    Chances are you’re drinking far more alcohol than you think.

    The reason? Wine, beer and spirits glasses are surprisingly deceptive, and most of us — even professional bartenders — are over-pouring the alcohol we serve.

    While too much alcohol obviously adds calories to your diet, other consequences of supersizing alcoholic beverages are even more worrisome. The health benefits of alcohol disappear and risk increases when you drink more than a few servings a day. And because over-pouring can double or even triple a standard serving size, many of us are technically “binge” drinking without knowing it, wreaking havoc on our livers and overall health.

    A standard “serving” for an alcoholic beverage is 5 fluid ounces of wine, 12 ounces of regular beer or 1.5 ounces of distilled spirits, according to the Centers for Disease Control and Prevention. All three portions contain 0.6 ounce of alcohol. But glasses today come in so many different shapes and sizes — tall “highballs,” wide tumblers, bowl-shaped wine goblets and now the new popular stemless wine glasses — it’s virtually impossible to estimate the right serving amount. Although a traditional wine glass holds about 7 ounces, many wine glasses today hold 16 ounces or more. Beer glasses often hold 20 ounces.

    “Often my clients think they are just having one or two drinks, when really they’re having more like three or four,” says Lisa R. Young, a New York University nutritionist.

    Try this experiment at home. Take your favorite wine or beer glass and use water to estimate drink size. Pour the contents into a measuring cup to see how close you come to the standard 5-ounce wine portion or 12-ounce beer portion.

    I did this myself, and was stunned by the result. I filled my favorite wine glass just half full. But I still ended up with 300 milliliters or 10.14 ounces — double the standard serving size. I tried again — this time with a smaller wine glass and then again with a large bowl-shaped goblet. But each time I still poured 200 milliliters or 6.76 ounces — 35% too much.

    . . .

    • Becca
      September 25, 2013 at 11:41 am

      Thank you for the link to the WSJ article, Bob! That’s fantastic! I can guarantee I pour too much in my glass each time. Maybe there should be little tick marks on every glass to indicate where a serving size is located 😉

      • Bob Henry
        September 25, 2013 at 11:00 pm


        At one wine store’s wine bar in the greater Los Angeles area, their stemware is “marked” with horizontal lines silk screened onto the side of the bowl to denote a “half pour” or a “full pour” sample of wine.

        (Of course, the stemware is of such mediocre machine-manufactured quality that you wish for hand pours in better stemware . . .)

        On a related subject, the late wine writer and educator Andrew Sharp in his book titled “Winetaster’s Secrets” [*] commented about environmental distractions affecting your sensory perception of a wine. Among them: music playing in a room, and the color of the painted walls.


        ~~ Bob

        [* Robert Parker’s book review:

        “An extremely well written book with the most informative and perceptive chapters on wine tasting I have read. This is the finest book for both beginners and serious wine collectors about the actual tasting process — lively, definitive and candid.”

        Backgrounder on author:

        Amazon book link: ]

        • Becca
          September 30, 2013 at 3:29 pm

          Thanks for all the great information, Bob! I’m curious about that book now! I’ll have to give it a read at some point and perhaps a review! Cheers!

        • Bob Henry
          September 30, 2013 at 6:47 pm


          I advise reading and reviewing the updated edition:

          ~~ Bob

        • David
          October 7, 2013 at 5:33 am

          Speaking of wine glasses, can someone recommend some that have a volume marking? (like 125 ml, about 4.2 oz) I have seen these in Europe but not in the US. I think that would be a big help as a cue on how much to pour. Thanks.

  3. William Gulvin
    September 24, 2013 at 10:19 pm

    The observation has been made that whether the glass is half full or half empty depends quite directly on whether one is pouring into it or drinking out of it. As for the related optimist/pessimist conjecture, an optimist thinks “this is the best of all possible worlds!” A pessimist is sure of it. Myself, I think I’ll have another glass of wine…

    • Becca
      September 25, 2013 at 11:41 am

      Cheers to that! *clink!*

    • jason
      September 26, 2013 at 5:31 pm

      Well it depends on what your glass is full of. If it has wine in it, I consider it half full. If it has crap in it, then I think of it as half empty.

      • Becca
        September 30, 2013 at 3:30 pm

        Ah yes, wise words! 🙂 Cheers to that!

  4. Jim
    September 29, 2013 at 11:39 am

    Many of the studies that analyze the relationship between wine consumption and health use data based on self-reported consumption. Do these studies suggest that people may systematically under report their wine consumption? If so, what might this imply about the effect of wine consumption on health? Is optimal consumption really one to two 5 oz glasses of 12% alcohol per day or might this be biased down if people typically under report their consumption? Any thoughts?

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