New wort right on top of old trub?

Let me know if this is a bad idea.

Lets say I brew a new batch and rack and old batch into the secondary the same day.

So I have a pot of cooled wort and a fermentor empty except for the trub/yeast of the old batch.


Can I just pour the new wort on the old trub and call it a day? Or do I need to clean/sanatize the fermentor and repitch all over again.


It will be a stout poured on the trub from a bitter. So I'm not worried about flavors getting mixed.

Dump it right on top! Think of it as a massive starter. And if it's the same brew, then you don't have to worry about undesired flavors from any wort/hop mismatches in the two beers.

Keep in mind that since you've got a TON of yeast in there, that your ferment could take off BIG TIME, so I'd recommend a pan or something under the primary, just to be on the safe side. And shake well

Pitching on the cake is a common way of getting a fast ferment on a really big beer. I almost always do this for my barleywines. The trick is to pitch the same day you rack the first batch. And as you noted, watch out for odd flavor combinations. Always move up in gravity, darkness and hops.

Thanks guys.

I love when people tell me what I want to hear

I guess having two worts worth of trub in the bottom of my fermenter is not a problem? There is already about an inch. I guess if I pour on that I'd get two inches of trub.

Not a problem. It'll probably ferment out in 2 days. And you'll also have to do a blow-off hose. Most of mine blow over when I do this with a 6.5g fermenter.