Why green olives come in jars, but black ones come in cans | Hacker News Reader

Why green olives come in jars, but black ones come in cans

marketplace.org

119 pointsbilalq72 comments

Open articleView on HN

Maybe it is a local (US) thing, here in Italy/Europe you can find black olives in glass jars just fine, a few examples:

http://www.polli.it/prodotti/olive/olive-nere-denocciolate-v...

http://shop.oliosalvagno.it/vasetto-olive-nere-in-salamoia-g...

https://pietrasantaaltosalento.it/it/home/19-olive-nere-in-s...

Yeah, in Canada Kalamata olives can be found in glasses (but black olives are in cans)

Canned olives in the US are a specific type which are artificially ripened. Is that the case with the olives linked in your post? (I can't read Italian.)

Same in France. Maybe it's specific to country that have to import olives from far away ?

Black olives are available in jars in the US as well. They are just a specialty item similar to higher end jarred green olives.

Black olives in a can and green olives in a jar are also available in commodity style qualities. So this is better labeled as "why are commodity black olives in a can while commodity green olives are in a jar".

Yeah, in Germany you can find both kinds in glasses, cans, or plastic pouches. However, I think most black olives here are simply green ones, colored with iron. I found it hard to find real black olives in my supermarket unfortunately.

Also, I think the botulism issue is prevented by having an acidic environment.

Similar situation in Finland (except olives in plastic pouches I have yet to see).

You can also order them in some sort of plastic container from Walmart: https://www.walmart.com/ip/Discontinued/37620615 (the URL says "discontinued" but it appears that you can still order them)

>Maybe it is a local (US) thing, here in Italy/Europe you can find black olives in glass jars just fine

In India too.

As others have noted, the article doesn't seem to answer the question it poses. What's missing is more detail around the process of producing green and black olives.

Watch the end of the embedded video:

https://youtu.be/xKWBJkaoRjM?t=1m7s

Black olives enter the canning facility unripe and green. Bubbling air blackens them.

This part of the process isn't mentioned at all in the article, and it's hard to know whether this was the process being used by Freda Ehmann, or whether/how this oxygen treatment resulted in the botulism cases.

All in all, not the best in technical reporting.

That part of the process doesn't seem relevant to how they are packaged.

If you read into this more, it's actually the lye solution which artificially ripens the olive. That Youtube video doesn't go into the lye process other than the chart that you can see on the wall while going over the 7 day process. My guess is they don't really want to be verbal that lye is used (sounds a little gross to me).

However, the gap between why black olives are prone to botulism and green olives are not prone is not covered. I wish that was expanded on.

Olives are slightly acidic by nature and the lye neutralizes that? Neutral environment, plus heat, plus low oxygen makes for Hollywoods funny faces.

ah that seems likely! Thanks

This may give a "better" explanation (though still unsubstantiated):

http://enquirer.com/editions/2001/06/25/tem_ask_a_stupid.htm...

http://www.straightdope.com/columns/read/2885/why-is-it-that...

http://lacrossetribune.com/tomahjournal/lifestyles/ask-your-...

It seems more like it has become a tradition of some kind in California.

More here:

http://oliveoilsindia.com/California-Olives.htm

it only applies to artificially made ripe olives.

Addition:

... and seemingly this "high temperature" sterilization (which is still within 110-120 degree Celsius, so perfectly doable in glass containers) adds acrylamide:

https://www.ars.usda.gov/research/publications/publication/?...

in almost unbelievable amounts:

http://pubs.acs.org/doi/pdfplus/10.1021/jf5022829

Heck! 410 micrograms/Kg vs. 1.4 (Greek Olives) and 0 (Spanish Olives)!

http://www.whfoods.com/genpage.php?tname=george&dbid=260

>What About Acrylamide and Olives?

Research on olives and their acrylamide content has shown some inconsistency over the past several years and this inconsistency has sparked controversy in the public press about olives and their health risk with respect to acrylamide. In data assembled by the U.S. Food and Drug Administration (FDA), we've seen more than a dozen different kinds of olives, including Spanish, Greek, Kalamata, Nolellata, Sicilian, d'Abruzzo, and Gaeta, and di Cerignola that were determined to contain no detectable level of acrylamide. Yet we have also seen FDA data showing levels of acrylamide as high as 1,925 ppb in some canned, nationally distributed brands of black pitted olives. Based on this data, we suspect that these higher acrylamide levels in select canned black olives were related to specific handling, storage, processing (especially preservation and darkening methods), and heating steps that favored formation of acrylamide. It's also important to note here that we are not aware of any data showing problematic levels of acrylamide in any extra virgin olive oils available in the marketplace.

At present, we are not aware of any foolproof method that consumers can use to avoid purchase of canned black olives that contain unwanted amounts of acrylamide. Since the FDA data has shown no detectable levels of acrylamide in numerous samples of important olives packed in brine, those olives may be worth considering as options that may help avoid unwanted acrylamide. As stated previously, extra virgin olive oil is another form of this nutrient-rich food that, to our knowledge, has not been shown in research to contain unwanted amounts of acrylamide.

I won't pass judgement on whether 410 micrograms/kg is an "unbelievable" amount, but I will just mention that it is 410 parts per billion, or less than 1 ppm.

Neither do I, but it is 400% the "traditional" olive contents, let's call it "substantial increase".

The last cited article reports however that as much as 1,925 ppb have been found in some specific canned olives.

For comparison, the FDA sampled a bunch of foods for acrylamide posted the values here:

https://www.fda.gov/food/foodborneillnesscontaminants/chemic...

Jesus, there is one Popeye's location that is apparently, just, like, going out of its way to add acrylamide to its french fry oil or something.

This whole data set is oddly fascinating.

I was surprised to read that the reason isn't that green olives are typically used to make martinis. It seems to me that having a jar of olives on a bar would make for a better appearance than a can. Also, green olives are typically stuffed with pimentos or garlic or blue cheese, and so being able to see them might help sell them, whereas black olives are used for things other canned vegetables are used for, ie salads, casseroles, etc.

Maybe my reading comprehension is shot but I didn't get a very clear answer to the question at hand.

Because in the 20s cans could be pasteurized to a higher temperature than jars could. Black olives in jars were killing people with botulism.

Green olives are pickled, so didn't require such high pasteurization temperatures.

Thanks, and what was the reason for pickling one kind of olives but not the other?

Green and black olives are one and the same species, but green olives are unripe so they are still growing on a tree, but black ones are ripe so they start falling down by themselves and you can pick them up from the ground, which is much easier.

The article states that she had a recipe for artificially ripening the olives. I don't think the olives are picked ripe.

"Pickling" may be an incorrect term here.

Green olives are unripe olives, black olives are ripe olives. Unripe olives contain very high levels of oleuropein, which is especially bitter and thus green olives cannot readily be eaten. Ripe olives have little, if any, of this compound.

To make green olives edible, they have to be cured (typically using a lye-based process for speed, but can be done with plain water over a longer period of time) to remove the oleuropein, and thus making them edible. After curing, they are typically kept in a salty brine to extend their shelf life.

Black olives do not need the curing process, but can be brined in either a salty water brine, or oil, or no brine at all via pasteurization.

I realized I left a few questions unanswered here, and for completeness' sake:

* Green olives can also be fermented (i.e. w/ yeast and bacteria, instead of using a lye- or pure-water 'cure'), to remove the bitter compound, and would thus be "pickled" in the traditional sense. These olives are not as green or firm as lye-cured olives.

* Why not pasteurize green olives, if you can do it with black olives? You can, but the heat would cause the green olives to become mushier, people expect green olives to be firm, and ripe (black olives) to be a bit soft. Soft green olives often are less desirable, outside of some specific preparations. (I.e. 'Greek-style' "crushed" olives.)

* Can you ferment, and thus pickle, black olives? Sure, why the heck not? Many Greek styles of black olives are done this way.

* Yes, you can pack cured green olives in oil too, like black olives. Anything to reduce the bacterial and oxygen activity in the olives will help to preserve them.

Thank you! May I ask for an encore?

What makes Castelvetrano olives so distinct and delicious? They are almost always a vibrant green with an apple-like crunchiness. To me this is like a completely different fruit. Is this just the genetic stock or are they prepared differently?

I put my due diligence into internet research, without satisfaction. Would love to hear from the experts.

No worries =)

Castelvetrano is one of those interesting olives for me, personally, in that I'm not a big fan since I prefer the richer, earthier flavor of the slow-cured (dry-cured are my favorite!) olives, but my wife loves them most of all b/c she doesn't like the earthier olive flavor.

So, it's one part plant, one part process that gives them their unique flavor. The olive its self has a bright, crisp flavor with a good buttery profile. The process used for these is an extreme example of the lye-cured process, where they are lye-cured for just a few hours, and then soaked in fresh, cold water for at most a couple of days (changing the water every few hours). Basically, one of the most minimal processing of the olive world. After this, they are generally kept in a lower-salinity brine than other olives, to avoid the "salty bite" of a standard olive.

So, the Castelvetrano olives are really an exemplar of how lye can be used to great advantage in curing olives, to create a unique flavor profile.

Your comments are far more useful to me than the article itself. Thank you.

It's at the end:

> The whole industry switched to a new standard for the ripe California olive.

> "It has to be heated to 240 degrees. And only a can would tolerate that, physically—you couldn’t do that with a glass jar."

> Eventually, California olives came back. In cans.

Just to nitpick that point in the article. You don't need high temperature. As long as you bring the contents to 100 celsius, all you need is time. They use what's called an f-value to determine at what temp and for how long they need to take. The 1 f-value is defined as 1 minutes at 121 cel. Normally for canned goods that will be stored at 25 celsius and lower, they aim for a 4 to 5.5 f-value. So, at 100 degress, to achieve that score would take 8.5 to 12 hours. Whereas at 121 it would only take 4 to 5.5 minutes. Now, what the texture and taste would be like after 8 hours at 100 I leave as an exercise to the reader.

This is a dangerous misconception. Bringing botulism spores to 100 Celsius will not kill them, the spores can survive indefinitely at these temperatures. This is literally the reason pressure canning was invented, to heat the liquid to a higher temperature such that botulism spores are destroyed.

No, no it doesn't. You two clearly didn't understand what I wrote. I don't how to explain it any simpler than I already have. Depending on the bacteria and the storage conditions of the canned goods, you might need to hold it to a higher f-value. For instance, canned goods that will be stored in a 25-40C range target an f-value of 12 to 15. The higher the temperature you use, the less time you need. And vice versa. It's a misconception that certain bacteria can only be killed at high heat. Quickly, sure. But, as long as you target the correct f-values, all you need is 100C. And a lot of time.

Is there a difference in heat-resistance between the bacteria and the spores?

Yes. The bacteria dies easier. But, the 12d process, and the f-values are formulated regarding the death of the spores.

From Wikipedia:

>Although the botulinum toxin is destroyed by thorough cooking over the course of a few minutes,[26][27] the spore itself is not killed by the temperatures reached with normal sea-level-pressure boiling, leaving it free to grow and again produce the toxin when conditions are right

Ah yes, a pithy phrase from Wikipedia that isn't backed-up at all by the sources. /golfclap

Here, read through all these, and then get back to me if you think you're still correct.

Perhaps this explanation will make it clearer?

http://www.nzifst.org.nz/unitoperations/httrapps2.htm

Something more scientific?

https://www.fda.gov/downloads/Food/GuidanceRegulation/UCM252...

http://aem.asm.org/content/early/2016/07/25/AEM.01737-16.ful...

https://www.food.gov.uk/sites/default/files/mnt/drupal_data/...

http://aem.asm.org/content/34/1/23.long

https://www.mpi.govt.nz/document-vault/11042

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC91518/

http://digitool.library.mcgill.ca/thesisfile115866.pdf

http://nfscfaculty.tamu.edu/talcott/courses/FSTC311/Textbook...

http://spo.nmfs.noaa.gov/mfr452/mfr4521.pdf

http://www.fao.org/docrep/010/ai407e/AI407E22.htm

A Nice explanation of thermal processing food for canning:

https://www.intechopen.com/download/pdf/40352

Textbooks?

Principles of Microbiological Troubleshooting in the Industrial Food Processing Environment See chapter 2.7

Compendium of the Microbiological Spoilage of Foods and Beverages Pages 20-24, 187-188, 210

The FDA source seems to be the best one, and was useful-- thanks for that. I'll concede that I (and it appears Wikipedia) are wrong on this matter.

For future reference, you could probably just list that, and drop the attitude. You should also avoid dumping a glut of studies that you didn't bother to read, and that turn out to be irrelevant to the study; for instance the NCBI study you linked was discussing lysozyme's effect on temperatures and appears to contradict your statements, while the AEM ASM study (34/1/23) doesnt back you up as none of the trials they did went below 104 C, and it showed an inverse logarithmic relationship with decreasing temperature.

I have read them all, but thanks for assuming I didn't. You know why I have an attitude, having to argue these points with people who are arguing based on ignorance and not any knowledge or facts of the matter. Perhaps, not commenting on subjects you know woefully little about would be the more prudent course in the future? This isn't a jab at you, just a general point of annoyance with commentators on the internet that always irks me.

That NCBI one shows C.bot being killed at temperatures under 100 celsius which doesn't contradict anything I said. See table 5. I never said all of them were to support my point of 100 c being fine. I posted ALL of those for people, if they wish, to educate themselves on the whole process, hence a couple textbooks, how the TDT in canning works, etc...

Actually it takes a temperature of 120 celsius to inactivate C. botulinum spores, which means you have to pressure cook any non-acidic foods that will be canned.

Nahh, the explanation is there, alright, though nothing supports the "240 degrees" theory (I have to presume they would be Fahrenheit degrees, i.e. 116-120 Celsius, and of course glass can bear that alright):

>The whole industry switched to a new standard for the ripe California olive.

"It has to be heated to 240 degrees. And only a can would tolerate that, physically—you couldn’t do that with a glass jar."

Eventually, California olives came back. In cans.

Even if it was 240 Celsius (which I doubt), glass can bear it just fine.

> of course glass can bear that alright

Perhaps not in the 1920s though.

Basic glass formulas haven't changed since long before the 1920s. Even borosilicate glass has been around since the late 1800s.

The setting point of jam is 105°C, so only very slightly cooler.

If I remember correctly from making jam with my mother, it's important to pour the really hot jam into the heated jars to ensure everything stays sterile -- so the jam going into the jars is around 105°C.

That's correct, but I've seen so many recipes on the internet that let the jam cool so the jars don't crack. That's ok for making a small amount to eat quickly, but for proper preservation you really need to do it hot.

It helps that my mother trained as a professional cook. That jam kept well for years.

I also remember it very clearly, as jam-making was by far the most dangerous cooking we ever did together. I could probably chart my maturity based on how much I was allowed to help, starting from washing the jars and putting them in the oven to sterilize, all the way to doing the whole process while she watched.

Its the jar seal that's the problem. Space age plastics have no problem with 240F, 1920s I donno they had to use wax or natural rubber?

Edited to add, and the jar too.

The Ball Perfect Mason Jar was introduced in 1913 with a bead for the seal to rest upon. That would have been under patent and expensive in the 20s. So the tech (barely) existed to vacuum seal pressure cooked canned food in the 20s but it would have been patented and too expensive compared to cheaper cans.

https://en.wikipedia.org/wiki/Mason_jar

Just take a second to think about that. 1913. The Romans could not have made such a jar. They lacked the material science. Things like this amaze me. A Ball jar is a simple item from my daily perspective. It is in reality a fairly advanced piece of material science.

So if you ever get flung back in time, probably your best best is evaporated sea salt. Then work your way up into simple cosmetics. You don't have the ability to create the supply chain necessary to create canning.

Dunno if the Romans couldn't have made it (their glassware was startlingly good for what we imagine was possible then, if you do a simple image search) but pre-Pasteur, people wouldn't have have conceived of a vacuum seal formed by heat and pressure as a food preservation technique worth pursuing.

Nor could they have made a rubber for the seal. They didn't have access to the plants (Nazi's tried to use the only source that would have been available at the time to the Romans and failed [1]). Think of the supply chain required to get rubber plants from Asian or the Congo to a Roman city. Carthage would have had a hard time too.

Even if they had rubber in enough quantity, they'd have to vulcanize [2] it to make it work. That was years, centuries beyond them.

1 - https://en.wikipedia.org/wiki/Natural_rubber 2 - https://en.wikipedia.org/wiki/Vulcanization Edited for the vulcanization.

True, not out of rubber. But remember that air-blocking seals were important for the control of the fermentation process in wine production and preservation, and it's not beyond possible that they could have refined cruder pitch and resin based solutions if germ theory had been better understood then.

To be fair, Romans not only mastered glass manudacturing (which in itself pre-dates them), they more or less invented (or however the material was first made during their period) "transparent glass" and - more than that - they invented "pressed glass", i.e. they were among the first to be able to mass produce glass objects, by blowing glass into pre-made moulds, JFYI:

http://www.ancient.eu/article/592/

So, they would have been able to produce glass jars alright and would have probably used (like it was done for wine and amphorae ) "sealing wax" together with cork (and/or some resins):

https://vinepair.com/wine-blog/history-wine-transport-8000-y...

And BTW, they were quite good at making airtight cans, too:

https://www.theguardian.com/uk/2003/jul/28/artsnews.london

(though most probably it would have been far too expensive to mass produce them at the time).

We need olives expert from HN - is this just USA (California) thing? I don't believe that black olives in Europe are actually artificially dyed with iron gluconate. My impression is that in Europe black olives are riped olives picked in late autumn or winter. Anyone to confirm?

Not an olive expert, but in Croatia (and probably the rest of Europe - Mediterranean) AFAIK green olives are picked in autumn, and black ones, that is full ripe ones, are picked in November and December. Those olives are used for the production of olive oil and they give the oil it's distinct golden colour... honestly, colouring olives sounds awful.

If you're in a rush, it was because jarred ripe olives caused a botulism outbreak, and only cans could tolerate the 240 degrees necessary to make them safe for consumption.

I'm missing something here. The article doesn't explain whether black color is the result of artificial ripening or not, and why it creates a risk of botulism (while green olives don't have it).

Botulinum spores need * Low Oxygen * Low Salt * Low Acid

Green Olives are only processed by being in a high salt solution that also contains some vinegar.(Or are lacto-fermented to create the acid.) Essentially they are brine-pickles.

Black Olives are soaked in Lye(very alkaline) until they are uniformly soaked, then put into a acid solution that helps develop their color(They are dark normally, but not uniformly black). The brine is lower in salt also. In order to make it safe for canning, they pressure can it to get to hotter than 240(I've always heard 250, but the article says 240).

Until the advent of modern polymer lined cans, salt would corrode the metal at the concentrations in green olives. So I doubt its a Black = metal can thing so much as...

* Automating pressure canning is easier/cheaper in metal. * Green Olives High salt, High acid, would corrode the metal. * Black Olives Lower salt, lower acid, could be metal canned.

Thanks for the explanation!

Are Kalamata olives not black? These are almost always sold in jars. I guess according to Eataly black is only the California ripe olive. I imagine the salami and olive expert who works at Eataly isn't going to comment on Greek olives. He's still wrong. The article should be about California ripes, not all black olives.

Kalamata olives are left to ripen to a deep purple (not black) on the tree, and are cured like other olives (brine or oil). California olives start green, and the curing process turns them black. See https://www.youtube.com/watch?v=xKWBJkaoRjM

But that is precisely what the article is about. Kalamata olives are neither black phylogenetically nor in color.

Throwing my antipodean hat into the ring to add to the growing chorus of "black olives come in jars".

You can just got to the international section or to stores which sell more international food, specifically Mediterranean or Middle Eastern. There are lots of varieties of olive, different sizes, packaged differently and so on.

I live in the Czech Republic and I can find both in glass jars.

So all black olives in the US are artificially ripened?

No, only the “California Ripe” variety

Hmmm. I almost always buy black olives packed in jars.

I find the account of the epidemiology investigation very intriguing with the whole seating chart and all. Cool stuff.

I've literally never seen a "can" of olives, is that normal in some weird part of the world?

The article is not about olives, rather about those black things that Californians eat on pizza and some salads. They neither look like nor taste like olives. :p

Reply on news.ycombinator.com