No DME for starter. Mash a batch of wort? Why not Dextrose?

[brewjedi]

So is there simply no substitute for a malt wort on a yeast starter? Has anyone tried using dextrose. We use it to bottle. If I'm stuck with mashing a mini batch of wort do I need to boil a full hour. I guess so to prevent off flavors. Honey? Cane Sugar?

[Bugeater]

Sugar and honey will work for bottling but won't work for starter. The purpose of the starter is for yeast propagation. As part of that process the yeast will adapt it metabolic processes to digest whatever food is in abundance and easily digestable. If you grow a batch of yeast that has adapted to sugars other than maltose, that batch will have a hard time trying to deal with the wort. You need to grow the yeast with the same type of food in the starter as what it will be using in the wort.

You can get away with sugar when priming because you don't have to worry about the health of the yeast once it eats that tiny bit of sugar.

Wayne

[brewjedi]

Thank you Bug Eater . I was pretty sure this would be the case. I guess I was just praying for an easy fix. Looks like the next step is a BIAB mash for four 1 liter starters. Wow, I need to reverse engineer a recipe for 1.040 OG and 4 liters wort at post boil. Time to do some math...

[BDawg]

One serious thing to consider if you plan on making a bunch of starter wort and storing it for later is the potential for botulism poisoning.

Wort pH is not low enough and even a normal boil is not enough to kill botulism spores. Only a pressure cooker/autoclave can do that. You run a very serious risk if you plan to boil up some starter wort and simply save it for later without properly canning it (using a pressure cooker).

This is one of those cases where there is a low probability but high cost to throwing the dice here. You can "win" a thousand times in a row with no ill effects, but it's that 1001st time that you lose can literally cost you your life, or at least cause major organ damage to your liver and kidneys. the reward of doing it the "easy way" will only save a little work either making a new starter or canning a batch up for later, while the risk is permanent. My point here is that you should absolutely do it right, don't fuck around with this shortcut.

HTH-

[spiderwrangler]

So is there simply no substitute for a malt wort on a yeast starter?

The dry yeast producers use 'non-grain substrates' to grow their yeast, I always kind of assumed they had another way making it into maltose sugars to keep the yeast working and happy. Wine and cider yeast can be grown up on non-malt mediums, since you don't need them to be be rocking and ready to eat maltose..

[brewjedi]

Don't worry Bdawg..... I'm making the whole 20 gals weds. 240 deg boil for 10 min will kill any spores but IDK how that temp will effect the wort. could be done in my pressure cooker but will the wort scorch??? one gallon finish wort does 4 starters thats not alot of liquid. any thoughts any one?

[BDawg]

No, it won't scorch in a pressure cooker, but there will be an absolute shit ton of hot break in the jars.

Just to be clear, you bottle it up in mason jars, screw on the lids, and pressure cook them in the jars. The pressure gets the temp up to 240 or so and that is what kills the spores. I like the 1 qt jars because 2 of them makes a perfect sized starter.
Simply cooking wort in a pressure cooker won't do it, because you need it to cool down INSIDE of the now sterile jar.

HTH-

[spiderwrangler]

Yeah, I read it as he was pressure cooking the whole thing...