Mixing old with new

May 5, 2012 8:41 AM

My wife likes to combine old things with new ones; everything from aspirin to maple syrup. If a new bottle enters the house, the old stuff from the nearly empty bottle gets dumped in. It feels wrong but I can't explain it scientifically. What's really wrong with doing that? Should I just get over it?
posted by JV to food & drink (43 answers total)

For medicine, I could see a problem because it does eventually expire. If you're constantly dumping old pills in with new, it would be possible for an old pill to find its way to the bottom of the bottle and be transferred again, or even multiple times. You might not consume it until it expires. It's kind of a remote chance, I think, but I wouldn't be comfortable with doing that.
posted by christinetheslp at 8:47 AM on May 5, 2012 [1 favorite]

If you were a stickler for process in chemistry class, if feels wrong because it feels like you're putting things into the stock bottle, which is a total no-no (from a chemical process perspective). It might matter less with maple syrup, aspirin, etc, but my chief worry here would be that you're mixing substances that could be close to or past expiration date with perfectly safe ones, without any way to distinguish the two or prevent contamination of the safe stock.
posted by zamboom! at 8:48 AM on May 5, 2012 [5 favorites]

you're mixing substances that could be close to or past expiration date

Exactly. If she wants to do this, any expiration date from the old bottle needs to be brought forward to the new bottle as well.

Also, the old bottle, just from being opened and closed numerous times, will have dust and germs in it that have gotten on the old stuff. This then gets dumped into the new stuff. Extremely unlikely it would hurt you, but it would squick me out a bit.

at first I thought you meant she dumped aspirins into maple syrup bottles into elmers glue into whatever, at least she doesn't do that, it would be way worse than this.
posted by hazyjane at 8:52 AM on May 5, 2012 [26 favorites]

I do this, with shampoo, maple syrup, most condiments and aspirin. I wouldn't do it with prescription meds that have an expiration date, but otherwise, I don't see what the big whoop is. Why have two bottles hanging around? I haven't poisoned anyone with ketchup yet.
posted by Ideefixe at 8:52 AM on May 5, 2012 [4 favorites]

I can't even conceive of being weirded out by this - if I take an "expired" aspirin, who gives a fig? Why would you want two bottels of crap lying around if you can consolidate?

I suppose if this were happening with stuff that truly expires in a week (meat, yogurt, whatever), but....syrup? That shit lasts for years.
posted by tristeza at 8:57 AM on May 5, 2012 [5 favorites]

In addition to the expiration issue, there's the possibility of mixing different brands of food products (like syrup) and maybe ending up with a taste you wouldn't like? Outside of these two, I can't think of any compelling reason why it's wrong. But I do sympathize with you because mixing "old" with "new" feels wrong in my gut as well. Even if there's no basis for it.
posted by helloimjohnnycash at 8:57 AM on May 5, 2012 [1 favorite]

I'm not sure I understand how this is coming up in the first place -- in order to make room for the old contents in the new bottle, doesn't she have to consume some of the new bottle's contents first? In which case, why doesn't she simply consume the old contents instead? As a practical matter this doesn't seem to make sense -- do you think this could be a compulsive behavior?
posted by foursentences at 9:02 AM on May 5, 2012 [14 favorites]

I can see the concern for aspirin, but maple syrup can only crystallise, and I can't imagine what could go wrong with glue. If something did, you're not eating it anyhow. (I don't know how glue came up exactly.)

Try to maybe figure out where this is an issue (things which can go bad) and ignore it where it's not.
posted by jeather at 9:02 AM on May 5, 2012

This would gross me out, for some reason. The medications I think are a definite no-no with expiration issues and all, but for some reason "old" food being mixed in with "new" food is just... wrong? I would dump the old stuff before I ~contaminated~ the new, but maybe that's just me. And, on preview, helloimjohnnycash.
posted by jabes at 9:02 AM on May 5, 2012 [9 favorites]

You could go all Martha Stewart and consolidate all of these things into decorative containers, like ceramic honey pots and jam servers, etc. and then no one would ever know how old the stuff is. And then you don't have to look at commercial packaging.
posted by Ideefixe at 9:04 AM on May 5, 2012

I do this with two things, coffee and oatmeal. Only because the packaging is so bulky that having two of them when there is just a little bit left in the bottom of the old one takes up too much precious real estate in the cupboards. Also because I feel pretty confident all of it will be used up well before a best-by date.

Agree with Ideefixe that decanting into decorative canisters is basically the same thing but seems less troubling.

I would not do this with medicines, or bother with anything in a much smaller package.
posted by ambrosia at 9:19 AM on May 5, 2012

I can see the concern for aspirin, but maple syrup can only crystallise,

I had a bottle of maple syrup go off really badly when it sat unused for a while. The bottle's open; contaminants can get in. And ketchup and other condiments seem to concentrate and get darker when sitting in a partially used container. I'd rather throw out an inch of ketchup than mix in new stuff, because the old looks so icky.
posted by BibiRose at 9:20 AM on May 5, 2012 [2 favorites]

I do this with individually packaged things wherein I can control the consumption of the oldest items first (popsicles, my daytrana patches, &c) but to do it with fluids, non-newtonian and otherwise, seems.... suboptimal at best, grotendous at worst.

I don't have the same feeling of unease re: aspirins as other posters here do because come the fuck on, I have imodium-esque tablets in my medicine chest that I brought back from Spain in 2005 and are still good.
posted by elizardbits at 9:27 AM on May 5, 2012

For food, fresh stuff tastes better - even if it's meant to stick around for a while. A new bottle of Sriracha tastes way different than the stuff that's been in your fridge for months.
posted by entropone at 9:37 AM on May 5, 2012 [3 favorites]

I can see the concern for aspirin, but maple syrup can only crystallise,

Syrup can mold. I keep mine in glass jars and then I can see if it's gotten crud in it, and I mix old with new all the time. I do this mixing thing with basically all dry ingredients [and medicines] but not with anything liquid other than syrup.
posted by jessamyn at 9:41 AM on May 5, 2012

Just so you know, restaurants do this with condiments all the time. That said I would never do this with medication.
posted by St. Alia of the Bunnies at 9:43 AM on May 5, 2012 [1 favorite]

Certain medications (notably tetracycline antibiotics) actually become dangerous after they expire. Most others will simply lose potency, although liquid stuff like nyquil could conceivably become more concentrated/dangerous as the water/alcohol slowly evaporates. I have heard that aspirin will degrade into vinegar when left in a humid bathroom medicine cabinet, but I've never verified it with a reliable source.

With food, I would never do this. Stuff gets contaminated, starts breaking down or spoiling, and to me it seems weird to mix the old getting-gross stuff into a nice, fresh, new supply. The trouble is that it seems more likely that people will try this approach with long-lasting condiments (syrup, ketchup), but those are the things that sit around forever, spoiling! I only do it with things that we use up really fast, like the oatmeal canister that we refill every week, and even then I make sure to empty it all the way every month or so.
posted by vytae at 9:45 AM on May 5, 2012 [4 favorites]

We do this with alcohol, dry goods (flours, oats, pasta, rice) and cat kibble, but not milk, syrup, honey, vinegars or other liquid sauce-like things. We do it for coffee, because the turnover rate is high, but not spices because the difference in taste with freshness is so marked.

I'm not sure I'd pick a battle with my spouse over it but I think lots of folks do it.
posted by crush-onastick at 9:46 AM on May 5, 2012 [3 favorites]

I think this could be a really bad practice, but that's because I have gone through my pantry and discovered foods well over a year past their expiration date.

So for me, I'd worry about that. It takes a long time for some foods (like maple syrup) to go bad, but I've found baking soda and baking powder lose their oomph after just a little while, and if you bake, that makes a difference--things don't rise correctly, or taste a little off.

Eggs are often already older than you might think when you buy them at the store. You need to use the oldest up first, for sure.

Consolidating into one container CAN be fine (everyone has storage issues), but only as if you have a method in place to use up the old stuff first, before it goes bad.

And, of course, medicines should never be combined.
posted by misha at 9:51 AM on May 5, 2012

Restaurants do it, but restaurants go through stuff like ketchup and syrup way, way faster than anyone at home would.

I don't do this at home but not because I think it will kill me. I want my fresh, new container of [stuff] to be truly fresh.
posted by TheRedArmy at 9:57 AM on May 5, 2012 [1 favorite]

If having two of something bothers her, I would just make an effort to use up the old one before opening the new one, so then there wouldn't be two. I don't think pouring old and new together, though, is a good practice.
posted by limeonaire at 9:57 AM on May 5, 2012

Here's some information about drug expiration dates from the Harvard Medical School:

It's true the effectiveness of a drug may decrease over time, but much of the original potency still remains even a decade after the expiration date. Excluding nitroglycerin, insulin, and liquid antibiotics, most medications are as long-lasting as the ones tested by the military. Placing a medication in a cool place, such as a refrigerator, will help a drug remain potent for many years.

posted by davcoo at 10:31 AM on May 5, 2012

Just so you know, restaurants do this with condiments all the time. That said I would never do this with medication.

Restaurants also go through condiments at a prodigious rate, such that any deterioration in quality is not likely to be perceptible. They also do (or should) clear and wash those containers on a regular basis.

As somebody who used to manage a sizeable retail food inventory, I don't see anything wrong with consolidation in principle, but I think there is a supervening principle that the oldest still-good product must be used first. Not an issue with dry goods, but anything that gets old in a time frame of months ought to just be used and cleared, and the container washed or discarded.

If your wife really wants to get the last little bit out of the shampoo bottle, for instance, it's just as easy to run a bit of hot water into the bottle to thin the stuff out when it starts to get low. You can cut it to like 50/50 with water and it still works just fine.
posted by gauche at 10:55 AM on May 5, 2012 [1 favorite]

Sadly, I have had maple syrup turn green and fuzzy.
I wouldn't mix old and new.

But I do this with shampoo and creme rinse all the time. And I just put all the gelatin packets in the house into the same box. And I buy tylenol and advil in 500 pill bottles and distribute it into smaller bottle to keep in convenient places.
posted by SLC Mom at 10:56 AM on May 5, 2012

From a food safety standpoint, it's just a poor practice. I'm not squeamish, will eat food ~long~ past the man's expiration dates, etc., but... if you have substance X (preparation 1) hanging around for a month, harboring a month's worth of oh-so-slow-growing bacteria... and then introduce substance X (preparation 2) with some small part from preparation 1, you just gave the bacterial growth in preparation 2 a month's headstart.

Or to put it another way, I've grown gourmet mushrooms, and what you describe is exactly how you get the fungus to quickly colonize a new, sterile medium... just put a small slice of colonized agar into the new stuff, and blammo, it's spreads like magic.
posted by BleachBypass at 10:58 AM on May 5, 2012 [10 favorites]

As far as aspirin and shampoo go... meh.
posted by BleachBypass at 11:00 AM on May 5, 2012

We called it "marrying" in the restaurant where I worked. But we did it with condiments that we went through quickly, and were all refilled from a larger container.

I marry things when combining the contents doesn't matter so much, like shampoo or the prescription meds I take every day. With foods, though, I'd rather just get rid of the old stuff before opening a fresh bottle.
posted by Metroid Baby at 11:08 AM on May 5, 2012

It's kind of a weird thing to do in the first place. Fresh things are almost always better. Why contaminate the new one with the age, dirt, bacteria, oxidization, etc of the old one?
posted by Cosine at 11:12 AM on May 5, 2012 [3 favorites]

I do this with salt, and that's it. Anything else and I feel it compromises safety, aesthetics, or (ketchup) both. I'm above-average in pickiness, though, and I'm not at all cramped in terms of pantry space.
posted by SMPA at 11:14 AM on May 5, 2012

We do this quite a bit, especially with bulk food stuff or things in big packaging. It's a space issue. The two things to consider are shelf life and turn over. For instance, we do this with coffee because I go through it pretty much weekly, which means even if I somehow manage not to get the beans on top first, the longest it's going to stick around is two weeks, not long enough for it to go REALLY bad, and it's small enough quantities not to effect the flavor of the brewed coffee noticeably.

You should decide things on an individual basis, I'd say take a look at the expatriation date, figure out how long that new bottle is going to last. If they're relatively close, I'd say go for it. Also consider if you know HOW the food goes bad. Is it a loss in quality or does it get truly spoiled? Loss of quality isn't nearly as important as spoilage.
posted by Gygesringtone at 11:16 AM on May 5, 2012

Maple syrup can only crystallize.

Actually not true. It's not honey, which has natural antibiotics built in. It will go moldy, which is why it needs to be kept in a closed container in the fridge
posted by zadcat at 11:39 AM on May 5, 2012 [1 favorite]

I think with syrup/honey, if you pour an older, crystallized batch into a newer batch, the newer batch will crystallize much more quickly, because you've just added a bunch of seed crystals. And while crystallization in itself isn't dangerous, it can cause the concentration of the remainder of the solution to drop, making it easier for pathogens to grow.
posted by Hither at 12:30 PM on May 5, 2012 [1 favorite]

Don't do this with drugs. They lose their effectiveness with age. Aspirin is a drug, and it will lose effectiveness with age.

Don't do this with foods. Food in containers is often pasteurised, and you are introducing established bacterial colonies from the old bottle into the new. This is especially true of things with a high sugar or fat content, as bacteria just loves that shit. Maple syrup is discussed up thread, and olive oils will go rancid over time too.

Shampoo, soaps and other cosmetics with high turn over, I suspect you would be okay with. Ones with slow turn over should not be mixed. Frangrances are usually fairly volatile compounds, chemically speaking, and will change over time, so you will be mixing a small amount of increasingly funky material in with your nice new product.

Things like glue, paper, and whatnot -ie, consumables with a long lifespan, and that are fairly stable chemically I see no issue with.

Frankly, why would you want to make extra work for yourself? Just use the old one up, bin it, done, rather than fucking about getting all the new and the old together in the same container.
posted by Jilder at 1:01 PM on May 5, 2012 [1 favorite]

Maybe it's not an optimal practice (and I don't do it) but the chances of anything harmful happening seem minimal. In the interests of marital harmony I would let it go. Unless it was truly bothersome, then I would say "I know this is silly but the idea of new and old food and medicines mixing really freaks me out. It's not rational but it would be awesome if you could do this for me." Trying to address it scientifically or as The Right Way To Do Things seems counterproductive.
posted by 6550 at 2:19 PM on May 5, 2012 [2 favorites]

Another consideration with OTC drugs (and possibly some foods) is that if there's ever a recall, you'll need to know the lot number or manufacturing code printed/stamped on the packaging to know whether your stuff is affected. It's a pretty rare occurrence, though, and this would probably only become a problem if the recall affected the contents of the old packaging that you'd already gotten rid of.
posted by Orinda at 2:59 PM on May 5, 2012

Unless you put your mouth on the maple syrup or ketchup, it should not be a problem. Ketchup is good for up to two years and I think maple syrup lasts for years and years. So, if you are not introducing bacteria (like saliva) into it, there isn't any trouble with putting the old stuff in the new stuff. Aspirin has an expiration date because the FDA makes you put an expiration date on all things you put into your body. There is no real expiration date for stuff like aspirin or cough medicine or the like. Liquid OTC medications may lose their potency after a long time, but it isn't going to go "bad." So don't worry!
posted by Yellow at 3:06 PM on May 5, 2012

OH! To address all of those with moldy maple syrup issues...you can scoop the mold out and bring the maple syrup to a boil and it is safe to eat. This info can be found in Chowhound. I have never kept maple syrup long enough to experience mold though.
posted by Yellow at 3:11 PM on May 5, 2012

Just the other day, I said to someone, "Yeah, I don't decant." So you are not alone in your misgivings.
posted by analog at 5:39 PM on May 5, 2012

I'd draw a distinction between one-time combining and perpetual combining. In most any of the cases that have been discussed, I'd be ok with topping up an existing container of something with a new batch of same - as long as the new batch is a small enough quantity to fit in the vessel, because otherwise you're still stuck with two containers, and as long as there's an expectation that the entire combined quantity will get used up within a reasonable time. Things like a flour bin to which you constantly add more, and never quite get to the bottom, seem like a bad idea.
posted by lakeroon at 7:43 PM on May 5, 2012

If it's something you go through pretty regularly, it's not a big deal. I wouldn't do this with, like, milk or something that spoils quickly, but aspirin and syrup? Wouldn't bother me in the least.
posted by elizeh at 9:22 PM on May 5, 2012

Thanks for all the great answers. It's not actually causing any marital distress, it's just one of our amusing debates... After reading all these responses I'm starting to see it's probably not a big deal in most cases - but it still feels wrong.
posted by JV at 4:12 AM on May 6, 2012

Well, in New York State, marrying liquor bottles is illegal. I don't think the feds are going to come knocking on your door, but if you're really concerned about that kind of thing.
posted by Lutoslawski at 12:28 PM on May 7, 2012

I really want to combine my interests and sketch "marrying liquor bottles" in DrawSome now.
posted by misha at 1:20 PM on May 7, 2012