# The last part of a bottle of drink is 20% saliva? **URL:** \ **Category:** Factual Questions\ **Created:** [May 25, 2001, 12:40pm UTC](https://boards.straightdope.com/t/the-last-part-of-a-bottle-of-drink-is-20-saliva/66473 "2001-05-25T12:40:47Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Mats\_K](https://avatars.discourse-cdn.com/v4/letter/m/8edcca/32.png) [@Mats\_K](https://boards.straightdope.com/u/Mats_K)\ **Post date:** [May 25, 2001, 12:40pm UTC](https://boards.straightdope.com/t/the-last-part-of-a-bottle-of-drink-is-20-saliva/66473/1 "2001-05-25T12:40:47Z")
My boss has this obsession of NEVER drinking the last gulp of a bottle of, say, coca-cola… He says that when he was younger with my his friends, and they were drinking a mixed 1.25 litre bottle (that’s a 40 ounce for the yanks here…) of scotch and coke, the last part of the bottle is 20% built-up saliva. Is there any truth in this? Mats K Melbourne ---
**Author:** ![Sauron](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Sauron](https://boards.straightdope.com/u/Sauron)\ **Post date:** [May 25, 2001, 12:46pm UTC](https://boards.straightdope.com/t/the-last-part-of-a-bottle-of-drink-is-20-saliva/66473/2 "2001-05-25T12:46:46Z")
I’ve heard this too; my wife says she never drinks the last swig of beer in a bottle for the same reason. Frankly, I think it’s bull. Of course, I have no stats or studies to back me up, so what good is that? ---
**Author:** ![RAWisSYDNEY](https://avatars.discourse-cdn.com/v4/letter/r/4491bb/32.png) [@RAWisSYDNEY](https://boards.straightdope.com/u/RAWisSYDNEY)\ **Post date:** [May 25, 2001, 12:48pm UTC](https://boards.straightdope.com/t/the-last-part-of-a-bottle-of-drink-is-20-saliva/66473/3 "2001-05-25T12:48:24Z")
even if it is 40% salvia it shouldnt gross them out if it is there own bottle… ITS THEIR SALIVA!! ---
**Author:** ![Mats\_K](https://avatars.discourse-cdn.com/v4/letter/m/8edcca/32.png) [@Mats\_K](https://boards.straightdope.com/u/Mats_K)\ **Post date:** [May 25, 2001, 12:54pm UTC](https://boards.straightdope.com/t/the-last-part-of-a-bottle-of-drink-is-20-saliva/66473/4 "2001-05-25T12:54:10Z")
Yeah that’s true Raw, but my boss is just so used to it from drinking with friends. I don’t know, I told him he’s a dickhead. Anyway, if the saliva is being built up, wouldn’t each person be drinking a percentage of it with each swig? ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [May 25, 2001, 1:00pm UTC](https://boards.straightdope.com/t/the-last-part-of-a-bottle-of-drink-is-20-saliva/66473/5 "2001-05-25T13:00:45Z")
One of my friends I use to hang with would leave about 3-4 good sized gulps in the bottle for that very reason. This really pissed the rest of us off as beer cost $. One time I took all of his bottles and pored the contents into one and gave it back to him as a new beer - he never knew the diffrence. if your beer was 20% diluted wouldn’t you know it - try it take 12 oz of beer and try adding 3oz of water - i bet you can tell. ---
**Author:** ![Quasimodem](https://avatars.discourse-cdn.com/v4/letter/q/e274bd/32.png) [@Quasimodem](https://boards.straightdope.com/u/Quasimodem)\ **Post date:** [May 25, 2001, 1:24pm UTC](https://boards.straightdope.com/t/the-last-part-of-a-bottle-of-drink-is-20-saliva/66473/6 "2001-05-25T13:24:27Z")
Grew up in Germany, where Cameraderie is very strong. Moved to the the US in '60 and developed different habits. Moved _back_ to Deutschland in 91-93 for work and made new friends. One night they were passing around a bottle of beer, each having drunk a couple of swigs, and when the bottle got to me, I politely demurred and hurt their feelings. Thing is , I don’t drink after _anybody_ has drunk out of the same vessel. It took a while, but they got the message. Still… Y’all ever run into this where _you_ live? Did you once do it and then stop because of the health risks? When I even think of it, it makes me wanna heave. 😛 Sorry if you were eating when I wrote this! Quasi ---
**Author:** ![bordelond](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bordelond/32/150_2.png) [@bordelond](https://boards.straightdope.com/u/bordelond)\ **Post date:** [May 25, 2001, 1:30pm UTC](https://boards.straightdope.com/t/the-last-part-of-a-bottle-of-drink-is-20-saliva/66473/7 "2001-05-25T13:30:04Z")
Uh … how exactly is ANY saliva getting INTO the bottle? The beer pours into your mouth, so saliva would have to fight against that “current” to go into the bottle. At the end of a swig, are people not swallowing the beer in their mouth before removing the bottle from their lips? Maybe then a beer/saliva mix would fall back into the bottle. That’s a heckuva sloppy (& unnatural) way to drink though – even if trashed. As for the GQ - IMO, that 20% figure is hogwash. ---
**Author:** ![Speaker\_for\_the\_Dead](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@Speaker\_for\_the\_Dead](https://boards.straightdope.com/u/Speaker_for_the_Dead)\ **Post date:** [May 25, 2001, 1:44pm UTC](https://boards.straightdope.com/t/the-last-part-of-a-bottle-of-drink-is-20-saliva/66473/8 "2001-05-25T13:44:14Z")
I’ve heard to this with straws, because apparently everything that touches the straw (which has been in your MOUTH) is suddenly mixed with saliva. :rolleyes: ---
**Author:** ![Threadkiller](https://avatars.discourse-cdn.com/v4/letter/t/aca169/32.png) [@Threadkiller](https://boards.straightdope.com/u/Threadkiller)\ **Post date:** [May 25, 2001, 2:53pm UTC](https://boards.straightdope.com/t/the-last-part-of-a-bottle-of-drink-is-20-saliva/66473/9 "2001-05-25T14:53:22Z")
> [@](#): > > \*Originally posted by Mats K \* > My boss has this obsession of NEVER drinking the last gulp of a bottle of, say, coca-cola… He says that when he was younger with my his friends, and they were drinking a mixed 1.25 litre bottle (that’s a 40 ounce for the yanks here…) of scotch and coke, the last part of the bottle is 20% built-up saliva. Is there any truth in this? The obvious question rears it’s ugly head: Does you boss ever drink the _second-to-last_ drink from the bottle? If so why? What is his “saliva threshold?” If he won’t swallow his own saliva he must spit a lot. OK I’ll quit. This has been covered (using science even!) by Ian York who posted his [results](http://www.urbanlegends.com/food/last_sip.html) to the [Alt folklore Urban (AFU)](http://www.urbanlegends.com) site. To summarize: > [@](#): > > Conclusion (Cheers from the audience) The level of ‘backwash’ saliva is less than 1% of the final sip. 1% was his detection limit so he assumes that the level is below that. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 25, 2001, 6:35pm UTC](https://boards.straightdope.com/t/the-last-part-of-a-bottle-of-drink-is-20-saliva/66473/10 "2001-05-25T18:35:05Z")
Also think of the volume of saliva we’re talking about here. Sometime, take an empty bottle, and see how much spit you can _deliberately_ get into it. Your mouth will go dry before you’ve even covered the whole bottom of the bottle. We don’t really produce all that much of the stuff. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [May 26, 2001, 12:47pm UTC](https://boards.straightdope.com/t/the-last-part-of-a-bottle-of-drink-is-20-saliva/66473/11 "2001-05-26T12:47:50Z")
I think this is silly. There must be some vanishingly small trace of saliva getting into the bottle, but for it to be a percent, much less twenty, would require far more production and throwing around of saliva than is really possible. Before I would throw away a big fraction of my beverage purchases, I would experiment a little - is the last bit of Coke less darkly colored than the first bit?