The Uncrustables Experiment


Lunches, like baseball, happens in series.  A couple of weeks ago, I had a series of Uncrustables for lunch, which are pre-made peanut butter and jelly sandwiches.  I’ll just come clean. I eat these all the time because I’m lazy. Making a real peanut butter and jelly sandwich requires planning ahead–buying the bread, peanut butter, jam–and then, requires using utensils, plates, napkins. Naturally, this leads to washing dishes. Basically, it requires A LOT. I just want to unwrap and enjoy.

Except, this word, enjoy, is the hard part. Uncrustables may have advanced the technology of scientifically-engineered bread, but they are gross.  And recently,  I declared on Twitter that I would never eat another one again. That’s what Twitter is for–witty quips about lunch. My roommate tweeted at me, challenging my Uncrustable declaration. That’s the other thing Twitter is for–communicating with roommates.

The conversation went like this:

Pizza – I swear I’ve eaten my last Uncrustable. These are disgusting and I keep buying them because I’m too lazy to make real PB&J sandwiches.

They don’t taste like Peanut Butter, Jelly, or bread. They taste like flavored gel pockets.

Roommate – One of these days, you will come to appreciate real food. But then you won’t have anything to blog about. Conundrum.

Also, I know you do not swear faithfully. On Monday, you will eat another.

Pizza– There must be something I’ve sworn off and stayed off.

Roommate – People who eat Uncrustables are lazy, uneducated, terrorist-loving hooligans. There.

Pizza – I have an idea for a for a scientific experiment. See how long an Uncrustable lives. Forever?

Roommate – I support this mission.

My roommate’s implication that the Uncrustable was not real food intrigued me. Of course it’s not real food. It’s a “Thaw N’ Serve” peanut butter and jelly sandwich.  The packaging refers to the product several times as a “Soft Bread” sandwich. What’s soft bread?

This calls for an experiment.  Using my fuzzy fifth-grade memories of the Scientific Method, (and reading “Steps of Scientific Method” on, I’ve decided to conduct an experiment.

First–the Big Question. How long is an Uncrustable’s shelf life, as compared to “real food”–a real peanut butter and jelly sandwich?

The next step is background research. Let’s take a closer look at the Uncrustable itself:



It looks innocent sitting there on that plate, but the Uncrustable contains nearly 50 ingredients, many of them preservatives, most of them unnatural. All your favorite food groups are here, like corn syrup, conditioners, diacetyl tartaric acid, ammonium sulfate, and 42 others.

And let’s take issue with the name, Uncrustables. It’s based on the idea that the crust on real bread is no fun to eat. Remember when your mother lovingly cut the crusts off? Now our Mother is Smuckers, mother of us all, and she has done it for us, leaving only the best part of the sandwich. The crust is now a…what shall we call it?  A “textured ring” that’s somehow ten times worse than crust.

The Uncrustable appears to be a relative of the Empanada family.


This is going to sound weird, but the Uncrustable in this picture reminds me of a drunk relative at a holday party, a few drinks in, red-nosed and smiling, teetering on his or her chair.

These sandwiches look as though they could be irresistable–bright candy-colored jelly, creamy peanut butter, fluffy white bread–but they are as resistable as a case of warm Miller High Life. Crammed with preservatives, these Frankensandwiches are overly sweet, chewy, and clay-like.

My Hypothesis is that with the sort of science used to engineer them, the Uncrustable could withstand mold forever.

The Experiment: I decided to create the complete opposite of an Uncrustable. I set the parameters of using only real foods:


The peanut butter’s only ingredient was peanuts. The jelly’s only ingredient was strawberries. And the bread’s only ingredient was grains.  I couldn’t bring myself to use a real plate. I really hate washing dishes. I did use a knife to spread the peanut butter and jelly. Science means you sometimes have to wash a utensil. It’s part of being a scientist.

My Real Food Sandwich:



For a control group, I kept an untarnished Uncrustable sealed in its wrapper.

I would be living with these sandwiches for the next 25 days, monitoring their decay. I suspected Real Food would begin to break down, mold and decay rapidly, while the Uncrustable would remain protected and preserved–plastic, the colors of fluffy clouds and candy reds. The Uncrustable would live forever–as it does in the freezer section, as it does in your stomach.

Day 3


On Day 3, there were aleady significant changes. The Uncrustable had begun expelling its insides into the plastic bag.



The sandwich looked ill, not well. Already, the soft bread was no longer soft–stiff to the touch. The creamy peanut butter and candy jelly had begun fusing together, a pudding of creamy brownish goop.

The pictures reminded me of the drunk holiday party relative, leaning over the toilet bowl, finished puking, but not yet ready to stand back up.

And meanwhile, Real Food was fine–


The bread was still pliable, perhaps a little darker in color.

The control group sealed specimen remained perfect in color, though it was slightly stiffer.

Day 7

The sandwiches have set out on the counter for a full week now.


Real Food was still soft. Shown here was the only blemish on the sandwich, a moist-looking spot on the edge of the sandwich.

And our Sealed Specimen looked okay, although it was hard as a rock now:


But the Uncrustable was on life support:


Serious color changes, more insides vomiting out. The strange weightlessness of a dead bird on a play ground.

Day 10

Real Food’s blemishes remained the same–the moist spot. By now Real Food had grown a little stiff, and while the color of the bread looked unhealthy, I would still feel safe eating this were it necessary for survival.


But the Uncrustable, and my hypothesis has fallen apart:


Day 10 – The Uncrustable has begun to mold.


The mold is even growing inside the goop. The Uncrustable is being eaten from the inside out. Sad. The jelly reminds me of the gashes on the Joker’s face.

Day 14

Today, the girlfriend and I were in my room upstairs. Downstairs, we heard my roommate come home and walk in the kitchen. She screamed.

“She must have saw it,” the girlfriend said.


It has grown worse. Much worse.


The Uncrustable is dead.

I have never seen mold so bright green before. The empanada ring is turning yellow. Fluffly whites and candy reds have given way to the colors of pukey yellows, greens, and browns. Even with the Ziplock barrier, I am weary of handling this thing very much. I am taking my picture and getting it out of my sight as quickly as possible.

Real Food is doing fine:


After two weeks, I am shocked to see that Real Food has resisted any signs of mold. The moist spot hasn’t grown at all. I guess mold doesn’t like Oat Nut bread.

And the Sealed Specimen of course, shows no changes —


Day 20

Today, this experiment had started getting to me. I was eating a pastry from the convenience store. I began looking at it closely, realizing it could have been made a month ago. It was slightly moist, sweating a little in its plastic wrapper. It reminded me of my sandwiches. I lost my appetite. Two bites in, I tossed it.

The Uncrustable is no longer dead. It’s now undead. It’s completely taken over by mold, a major health hazard, and about to become self-aware. The following images are utterly disgusting.



The Bionic Real Food is still not molding, although finally, after 20 days, is beginning to look gross. Were it a question of survival and I was looking at this sandwich, I would probably opt to hold out for another day in hopes of rescue:


The jelly is congealed, a healing wound between two slices of undestructable Oat Nut bread:


Day 25

The final day. Thank God.


The Uncrustable is now burning in hell.

Real Food remains soft, but denser–heavier, wetter, like a pile of wet rags.

Sealed Specimen feels like drywall. It was time to open her up and do an autopsy.


As you can see, the empanada part has turned yellow, much like the other Uncrustable had on Day 7. And like Real Food, the sandwich developed a moist spot–only this spot spanned half the sandwich. And then the insides –


Brown. Remember the nice separation, the candy red between two lips of peanut butter? Brown. Oh god, Brown.

Glue. The smell of glue, fermentation. Red wine. Oh God, Glue.

Conclusion: These things do not hold up. The Scientific Method states you should also repeat your experiments several times to make sure that the first results weren’t just an accident. This was no accident. My hypothesis was simply dead wrong, though perhaps I have gained something from the experiment.

I stand by my earlier declaration: I swear I will never eat another Uncrustable.

But then, I don’t swear faithfully, and there’s always Monday.

20 thoughts on “The Uncrustables Experiment

  1. This is fascinating. I expected the Uncrustables to last forever. Standard issue embalming fluids probably have fewer preservatives.

    Strangely enough, I kind of feel like eating one right now.

  2. Good work. I’m impressed with your scientific skill and your acceptance of drawing and unexpected conclusion. Have you eaten an uncrustable since??

  3. Gross.

    You should try eating some food that’s not pre-packaged. It’s delicious… and you’ll live a longer, happier existence… and you’ll be able to provide awesome blog entries like this one for years to come.

  4. they should both be put in the same type of sealable sandwich bag.
    to eliminate the variable of one plastic possibly being more porous than the other.
    meaning one could provide more airflow than the other thus altering the results.

  5. hmm. i feel like you are using propaganda. even though your hypothesis turned out to be wrong, you still say that uncrustables are extremely unhealthy. why? they break down easily, its not like they would rot like that in your body, they would be out by then, and broken down inside your stomach. i dont really understand.
    Just sayin’

  6. Wait… the uncrustable broke down! On the other hand, the ‘natural food’ repelled the natural molds that grow on any food! Doesn’t that mean your ‘natural’ sandwich is loaded with more potent preservatives, while the uncrustable sandwich broke down like normals food?

    1. Thats how I feel, I mean, doesn’t that mean that the uncrustables ARE healthy enough, and that they WILL in fact break down in your stomach just like any other normal food???

  7. This is exactly what I was looking for! I left an Uncrustable (PJ&Grape Jelly) on my desk at work for a week while I was on vacation. I am sitting here today wondering if I should eat it….it has only been 7 days but seeing that mold beings to happen around 10 days, I feel compelled to refrain!
    Thanks for posting this, I think you may have saved me from an un-wanted trip to the bathroom!!! LOL

  8. your so called “real food” seemed to be MUCH more processed than the uncrushable. The amount in the preservatives in that bread must be dangerous for it to not mold at ALL for that long

  9. All of your products used for the “real food” sandwich seem to be even more processed and contain even more preservatives than the uncrustable. You should have read the labels. You need to re-do this experiment with the organic & preservative free 365 brand from whole foods. I shop only at whole foods to stay away from preservatives and pesticides and any bread product you buy there must be frozen or refrigerated immediately, otherwise it will mold in a day or two.

  10. I see something something wrong with the non-sealed uncrustable on day 7.
    I was examining the image of the uncrustable on day 7 and I found a blueish spot on the edge of the slice on the left half of the sandwich. Are you sure that’s not a mold?

  11. People. jelly needs refrigeration, If you leave one in your lunch pail overnight (24hrs later) and you are not sure if you will get sick.,there’s a saying; When in doubt throw it out.

  12. This experiment made my 9yr old laugh as I was trying to prove a point of letting your uncrustables thaw all the way. It passed some time to wait for it but pretty sure it was still mostly frozen when she ate it.

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