The Great Bread Experiment: Week 2

“Now with even more gratuitous mold photos!”

Between days 7 and 13 days the mold really started to attack the four white bread samples that are part of the Great Bread Experiment. However, as predicted, the bread being stored in paper bags isn’t afflicted by the same green fuzzy mold that’s covering from 5% to 95% of each of the plastic-bagged slices…at least not yet. (You can check in on Week 1 results here.)

Since the magic is happening in the plastic, I’m not going to say much more about the paper bag samples, other than to say they’re dropping water weight like a boxer before a big fight, and to advise you to store your bread in plastic if you want it to last longer at room temperature.

Remember the four types of white bread being tested are:

  • Baked “in-store”
  • Wonder Bread Classic
  • Artisan
  • Homemade (bread machine)

Baked in store

As you can see, a large green bullseye has appeared on the centre of these slices. The samples housed in paper are still relatively soft but not bouncing back quite as fast when compressed; kind of like your skin when you’re really dehydrated.

Baked "in-store" bread after 14 days stored in plastic (left) and paper (right)


  • Paper – 43 grams paper (-11 grams since day 1)
  • Plastic – 73 grams (+1 gram – huh?)

Wonder Bread

Wonder bread is an enigma. Despite claims that it contains “free of artifical preservatives”, Wonder was the last bread to show any mold. It wasn’t until day 13 that I spotted a faded thumbprint-sized spot on the back of one slice. (The fact that even mold doesn’t find Wonder Bread enticing doesn’t bode well for us humans!)

Wonder Bread after 14 days: no mold

Its texture is still soft and spongy, just like day 1.

Slight mold spot on Wonder Bread after 14 days stored in plastic


  • Plastic: 107 grams (-1 gram)
  • Paper: 79 grams (net loss 22 grams)

Homemade – bread machine

With mold pockmarks making their way to the surface of the homemade slice, I’m impressed at how well this preservative-free loaf has held up. Denser than the other breads from the beginning, the bread machine slices are still slightly pliable; they feel meaty like a medium-rare grilled Portobello mushroom.

Homemade bread machine bread after 14 days stored in plastic (left) and paper (right)


  • Plastic: 73 grams (-1 gram)
  • Paper: 54 grams (-20 grams)


The preservative-free bread I bought at the Farmers’ market was the first one to show signs of mold. Between days 7 and 10 the colony was established and by day 11, spores were affixing themselves to the inside of the plastic bag. I’m guessing this sample is the reason my dining room (where I store the bags) is starting to smell musty and organic. After two weeks, fluffy blue mold is covering almost every square centimetre of the artisan bread’s surface, making it look like a tie-dyed Easter egg.


I’m loathe to touch it.

It’s the only bread that didn’t stay soft; it’s crusty even in the plastic.

Artisan bread after 14 days stored in plastic (left) and paper (right)


  • Plastic: 62 grams (net weight loss = 2 grams)
  • Paper: 40 grams (-17 grams)

What have we learned?

Despite boasting “no preservatives”, Wonder Bread mysteriously outlasted all other types of bread, showing signs of mold three days later than the closest runner-up. Is there anything in this ingredient that would be a red flag to you?

Ingredients: Unbleached wheat flour, water, sugar, yeast, soybean and/or canola oil, salt, natural sour flavour (bacterial culture), cultured wheat starch solids, soy flour, vinegar, soy lecithin.

It looks like all four types of bread are harbouring the same type of mold, at least to the naked eye. Not that it matters – if bread is moldy, I think a good rule of thumb would be: Don’t eat it! However, at least in cool, dry conditions, you have nearly a week before the first signs of mold appear in a typical loaf. It’s more the texture that’s affected.

The experiment continues, perhaps for one more week…I’m curious as to when Wonder Bread actually gives in to the mold. Then, do I need to find a place to dispose of this biohazardous waste?


The experiment will continue until Wonder Bread sprouts spores. Will keep you posted.

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