# Telling Jams Apart -- Need Help Fast **URL:** \ **Category:** Factual Questions\ **Created:** [December 11, 2023, 9:23pm UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446 "2023-12-11T21:23:37Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [December 12, 2023, 10:50pm UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/41 "2023-12-12T22:50:21Z")
My grandma used to make plum jam leaving the stones in, and usually warn people to watch out for them ---
**Author:** ![pjd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pjd/32/3009_2.png) [@pjd](https://boards.straightdope.com/u/pjd)\ **Post date:** [December 12, 2023, 11:08pm UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/42 "2023-12-12T23:08:41Z")
It’s quite simple. You get three people together, and put a jar of jam/marmalade on their heads, and tell them that at least one has cherry jam on his/her head. One of them should eventually be able to deduce the type of jam/marmalade on his/her head. ---
**Author:** ![CairoCarol](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cairocarol/32/3825_2.png) [@CairoCarol](https://boards.straightdope.com/u/CairoCarol)\ **Post date:** [December 12, 2023, 11:34pm UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/43 "2023-12-12T23:34:15Z")
> [@Mangetout](#): > > What do you ask to find jam you want? Hold up a jar and ask either guard, “If I asked the other guard what flavor this is, what would his answer be?” The flavor will be the answer you _don’t_ get. I assume that’s the right answer. Do I win a prize (maybe a jar of jam) for answering correctly? ---
**Author:** ![Buck\_Godot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/buck_godot/32/6573_2.png) [@Buck\_Godot](https://boards.straightdope.com/u/Buck_Godot)\ **Post date:** [December 12, 2023, 11:38pm UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/44 "2023-12-12T23:38:55Z")
If I recieved such a gift, I would find that the cute anecdote regarding their origin would make it even better, then getting labeled jam without the anecdote. The only suggestion I might make would be as much as possible to leave the jars in the order in which you found them and then deal them out to the recipients like a deck of cards, 1 to each, then a second to each, then a third to each. Chances are that the batches haven’t been completely randomized, and so sorting them this way might make it more likely that the recipients didn’t get all of the same type. ---
**Author:** ![thelurkinghorror](https://avatars.discourse-cdn.com/v4/letter/t/7c8e57/32.png) [@thelurkinghorror](https://boards.straightdope.com/u/thelurkinghorror)\ **Post date:** [December 14, 2023, 7:27am UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/45 "2023-12-14T07:27:47Z")
> [@Q.Q.Switcheroo](#): > > You are in a room with two jars of jam, both labeled “BLUEBERRY JAM.” You point to one of the jars and say, “Either this jar contains blueberry jam, or the other jar contains cherry marmalade.” In fact, unbeknownst to you, both jars contain cherry marmalade. Did you have knowledge of the truth of your statement? Simple, I put iocane powder in both jams. > [@InternetLegend](#): > > I made a pie like that once! It taught me not to be lazy and freeze cherries before putting them (or to label them clearly). It sure did look nice, though, with all those plump round cherries! Wouldn’t freezing them first make pitting somewhat easier? It does for some fruit but I’m not sure about cherries ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [December 14, 2023, 12:06pm UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/46 "2023-12-14T12:06:12Z")
> [@pulykamell](#): > > Cherry clafoutis is sometimes (often? usually? traditionally?) made with unpitted cherries. Traditionally. I have made it that way, but generally don’t. > [@thelurkinghorror](#): > > Wouldn’t freezing them first make pitting somewhat easier? No, cherry stoners work by pushing the stone out through the soft cherry flesh at the stem end. If the cherry is frozen, the stone won’t pop out as easily. ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [December 14, 2023, 12:12pm UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/47 "2023-12-14T12:12:44Z")
> [@DSeid](#): > > A jam roll? I thought it was a jelly roll? Ah but then we have the test: it must be jam cause jelly don’t shake like that. That’s actually a good idea! I never buy a jelly roll because they are cheaply and horribly made. However, a quality cake combined with your gourmet jams would probably be rocking! ---
**Author:** ![thelurkinghorror](https://avatars.discourse-cdn.com/v4/letter/t/7c8e57/32.png) [@thelurkinghorror](https://boards.straightdope.com/u/thelurkinghorror)\ **Post date:** [December 15, 2023, 4:40am UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/48 "2023-12-15T04:40:39Z")
> [@MrDibble](#): > > No, cherry stoners work by pushing the stone out through the soft cherry flesh at the stem end. If the cherry is frozen, the stone won’t pop out as easily. After thawing, to be clear! ---
**Author:** ![InternetLegend](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/internetlegend/32/13154_2.png) [@InternetLegend](https://boards.straightdope.com/u/InternetLegend)\ **Post date:** [December 15, 2023, 4:49am UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/49 "2023-12-15T04:49:11Z")
Defrosted cherries are much more slick and difficult to handle than fresh ones. They also lose a lot more juice when you pit them, so they can end up kind of “tough” (comparatively) in a pie. Also, and this is a huge issue for me, refreezing them leads to an immense loss of quality, so you have to defrost and pit them the same day you make your pie. ---
**Author:** ![Baal\_Houtham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/baal_houtham/32/13604_2.png) [@Baal\_Houtham](https://boards.straightdope.com/u/Baal_Houtham)\ **Post date:** [December 15, 2023, 5:06am UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/50 "2023-12-15T05:06:31Z")
Here’s a possible technique to distinguish: Do you have DSLR-style camera with an external flash — the kind of flash that mounts on the camera’s hot shoe? (Let’s assume Yes for a moment.) Set the flash to full manual power, tape the jam jar to the flash, focus on a white wall in a darkish room and shoot a test shot. See if the wall is visibly tinted. Change the aperture to make the image lighter or darker. (We have the camera set on Manual Exposure.) With luck the different jams will yield photos with distinct tints. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [December 15, 2023, 7:05am UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/51 "2023-12-15T07:05:16Z")
> [@thelurkinghorror](#): > > After thawing, to be clear! Possibly, I wouldn’t know, I always stone my cherries before freezing them. ---
**Author:** ![Munch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/munch/32/5281_2.png) [@Munch](https://boards.straightdope.com/u/Munch)\ **Post date:** [December 15, 2023, 12:54pm UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/52 "2023-12-15T12:54:10Z")
There are 100 jars of jam in prison. None of them are allowed to speak to each other (which makes sense, because they’re jam), and they cannot leave until they decide how many of them are blueberry, and how many are cherry marmalade. There may be one rogue jar of loganberry preserves in there as well. If one jar is allowed to make a guess to a guard each day, how many days until they are freed? ---
**Author:** ![Pardel-Lux](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pardel-lux/32/20182_2.png) [@Pardel-Lux](https://boards.straightdope.com/u/Pardel-Lux)\ **Post date:** [December 15, 2023, 1:58pm UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/53 "2023-12-15T13:58:15Z")
The number of days would be the logarithm of the number of jars squared, also known as [log-jam](https://en.wikipedia.org/wiki/Log_jam)², more or less. In your example, 100 jars, log 100 = 2, 2² = 4. More or less. Probably more. ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [December 15, 2023, 2:37pm UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/54 "2023-12-15T14:37:15Z")
You are in a room with three doors. Behind one door is a jar of cherry jam, behind a second door is a jar of blueberry marmalade, and behind the third door is a goat. You pick one door and open it, and find that the goat has eaten the contents of both jars. What kind of goat stew will you have for dinner? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [December 15, 2023, 2:45pm UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/55 "2023-12-15T14:45:33Z")
There is a box containing a jar of fruit preserve and a cat; if the jar contains blueberries, the cat dies; if the jar contains cherries, the cat survives; until the fate of the cat is known, the jar contains bluecherryberries. ---
**Author:** ![Q.Q.Switcheroo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/q.q.switcheroo/32/5713_2.png) [@Q.Q.Switcheroo](https://boards.straightdope.com/u/Q.Q.Switcheroo)\ **Post date:** [December 15, 2023, 2:49pm UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/56 "2023-12-15T14:49:34Z")
Goat surprise! That’s goat without blueberries or cherries. ---
**Author:** ![Orville\_mogul](https://avatars.discourse-cdn.com/v4/letter/o/aeb1de/32.png) [@Orville\_mogul](https://boards.straightdope.com/u/Orville_mogul)\ **Post date:** [December 15, 2023, 8:11pm UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/57 "2023-12-15T20:11:10Z")
Longshot here, but if the density of the orange peels is different enough from the berries, maybe you could try to make a homemade centrifuge with pantyhose (or similar) and a rapidly rotating arm? ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [December 15, 2023, 9:27pm UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/58 "2023-12-15T21:27:02Z")
Yes! A jar of jam in a home-made centrifuge. What could possibly go wrong? Be sure to video the process. ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [December 15, 2023, 11:21pm UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/59 "2023-12-15T23:21:36Z")
> [@Mangetout](#): > > What do you ask to find jam you want? You ask one of the guards, “If you were a truthteller, would you say this jar is cherry?” He’s got to give the correct answer. Even better, “If you were Ray Smullian would you tell me this jar is cherry?” I love this thread. Happy holidays everyone. ---
**Author:** ![anny\_m](https://avatars.discourse-cdn.com/v4/letter/a/96bed5/32.png) [@anny\_m](https://boards.straightdope.com/u/anny_m)\ **Post date:** [December 17, 2023, 12:55am UTC](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446/60 "2023-12-17T00:55:13Z")
Thanks, everyone, for all the responses – the practical and the humorous. I enjoyed them tremendously. If I’d been smart I’d have addressed the “What kind of jam is this?” in October when I made them instead of waiting until mid-December when I needed to get them boxed up, and the out-of-town ones mailed. In October, I’d have had the time to try some of the suggestions. Of course, if I’d been smart I’d never have mixed them up in the first place… In case anyone is curious, I labeled the jars: Mystery Jam Blueberry Marmalade or Cherry Jam Then on the card I put in the box, I said: _So, I screwed up – I didn’t label the jam right away and now I don’t know which is which. You’ve got (1 jar/2 jars) of Mystery Jam, which could be:_ The box insert cards list the ingredients. (Everyone got 3 jars of jam, so some got no Mystery Jam jars, some got 1, some got 2.) I made sure the jar that I could tell was Blueberry Marmalade, went to a dear friend who enjoys it so much that in the past she’s given me blueberries in the hope I’d turn them into marmalade. [Previous page](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446.md?page=2) [Next page](https://boards.straightdope.com/t/telling-jams-apart-need-help-fast/994446.md?page=4)