Do you guys have best plan to store longer for sugar wort to propagate yeast ? I usually take wort after boiling step during brewing and stored at 5 C inside 20 liter container. Or Boil with DME for starter ?
One easy and convenient way to store sugary wort in order to make futur starter is to freeze it. You can store your frozen wort in your freezer for a long time (i'd say at least 6 month).
I would advice you to separate your wort into little smaller parts so that you can only unfreeze what's needed when it's needed.
I heard pressure cooking the wort is a great way to make your wort storable for couple of months: https://www.themadfermentationist.com/2014/11/pressure-canning-starter-wort.html
Never tried it myself, due to the lack of a pressure cooker.
The method I’ve yet only heard of, used by breweries and homebrewers alike, is to boil the wort for 10-15 minutes and freeze it. This would also is in line with traditional German Reinheitsgebot.
Personally I use DME for starters.
Best of luck!
Edit: Some yeast labs suggests using a wort of 1.040 to avoid ethanol production when making a starter. Higher gravity may inhibit cell growth.
Put your boiled wort right into a corney while hot. This sanitizes the keg much like heat does in canning.
Store it with your beer in the keezer.
Use a fresh sanitizes picnic tap and line when drawing for use. Attach cO2 at 2 psi just enough to push it. Then remove a fittings.
If done right you don't even need a boil when doing starters. But bringing the wort to a boil for 3-4 minutes and chilling insures sanitation.
I'll do 5 gallon wort brews, or use second running s and bump to 1.040 with extracts