Saturday, October 09, 2010

Does the edible percentage of an avocado depend on its size?

Berkeley Bowl Marketplace in Berkeley, California is justly famous for its vast array of produce, and their avocado selection is no exception. They sometimes sell five different sizes of the fruit: pee wee, small, medium, large and extra large (almost all Hass variety). Naturally, they are at different prices and always by the piece, never by weight.

For a while I've been wondering two things about them: 1) does the fraction of edible material depend on the size of the avocado? and 2) what are the relative costs of the different sizes?  To answer these questions, I've been buying various sizes of Hass avocados from Berkeley Bowl and other places for the last few months and recording the weight of the whole fruit and the edible portion before eating. 

To date, I have weighed 19 avocados: 6 large, 6 medium, 3 small, 2 pee wee, and 2 extra large. The results of my measurements are in the chart below. The x-axis is the weight of the whole avocado in grams; the y-axis is the percent of the avocado that is edible, by weight. The different symbols represent the different sizes. The edible percentage is consistent across the span of weights, centered around 70%*, meaning that the amount of flesh you get from a Hass avocado is relatively independent of the total weight.  The 70% result is consistent with UC Riverside's Avocado Information site, which states that the seed, skin, and flesh percentages for Hass avocados are approximately 16%, 12% and 72%, respectively.

I don't know enough about avocados to say why the flesh percentage is so consistent across avocado weights. It might be the case that as avocados grow, the mass is added to the pit, skin and flesh at roughly the same rates. Or that when an avocado is ready to be harvested, the edible percentage happens to be around 70%. Whatever the case, what the graphs means for you is that choosing the heaviest avocado is likely to give you the most edible flesh, as opposed to a disproportionately large pit or thicker skin on a larger avocado.

I also recorded the cost of each avocado and calculated the cost per edible weight. Those results, however, are too messy and inconsistent to show here for a few reasons: prices varied during the experiment (it would have been better to buy, say, 10 of each size at one time), sometimes I bought organic avocados without recording that fact, some avocados were from the farmers market, and so forth. In any case, the results in the chart above can help you comparison shop.  Here's how:  given two avocados with different prices, weight each one, then calculate the ratios of the weights and the prices, with the larger avocado in the numerator. If the weight ratio is greater than the price ratio, the larger one is a better deal.  For example, a $0.99 "large" avocado weighing 260 grams vs. a $0.89 "medium" avocado weighing 190 grams.  The price ratio is 1.11, the weight ratio is 1.37, so the large avocado is the better deal (approximately $2.50 per pound of flesh for the large vs. $3.02 for the medium).

If you have any avocado data, want to send me some in the future, or know of already published sources, leave a comment or send me an email and I'll update the chart. What I need to know is the variety of avocado, the weight of the whole avocado, and the weight of avocado flesh (or the weight of the skin and pit). If you have a size grade (small, medium, large), that would also be useful.

As a final note for this post, here is an avocado mystery to ponder: Why are they sold by the piece and not by the pound? I personally have never seen avocados sold by the pound, and it doesn't make a lot of sense why not. Grocery stores already sell lots of different fruits and vegetables by weight. I asked the California Avocado Commission if there is a good reason for this, and they told me that it is completely up to the retailer to decide how to price their products.

* Except for the small avocados, which had a far lower edible percentage. Perhaps I wrote down the wrong weight in my notebook.

Photo of an avocado half from Andrea.Pacheco's flickr collection, subject to a Creative Commons License.

Random link from the archive: The Modern Burrito, a 'Fusion Food'

Technorati tag: Food


SP said...

Another interesting post. Thanks!

The Sick Earth said...

exactly what i was looking for

Chris Mc. said...

Thanks for the article. It resolved a question I'd long had: "do you get more avocado for your money with big or small avocados?"

BY the way there's more info here:

Marc said...

Thanks Chris Mc. for the link to the avocado article. I'm glad my experiment was helpful.

Table 5 in the avocadosource article has some percentage measurements for Fuerte and Hass avocados. Using a sample of 10 Fuerte avocados (average weight 249 g), they found that the average weight of edible pulp was 72.3% of the original weight. Using a sample of 20 avocados (average weight 249 g), it was 70.7%. Those are in the same range as my measurements.

miri dahan said...

Fantastic! I've been wondering about it for years, and could never bring myself to weigh the avocados.

Now I can buy the small ones without worrying about losing content!