Carbonation Idea

[barnumbrewing]

Instead of using priming sugar, has anyone used a small amount of sweet wort from the original boil to carbonate your bottles?

 

[KeystoneHomebrew]

That's actually an old technique called Krausening. A lot of German breweries still do it as sugar is a no-no for bottle conditioning.

Here's a good link for ya.

http://www.winning-homebrew.com/krausening.html

 

[Captain Damage]

Krausening uses still-fermenting beer. Speise uses not-yet-fermented wort.

Couple threads on it:
https://www.homebrewtalk.com/f14/speise-344973/
https://www.homebrewtalk.com/f35/calculating-correct-amount-speise-348331/
A search will show you a few more threads on it.