Fruit During Primary

I add puree or juice to the primary after the 5th day with good results. Adding it sooner could theoretically expel more fruit aroma than desired.

I secondary whole fruit to avoid excessive splashing.

 

I see what you did there.

 

What I've been told is that you want to add the fruit as late as possible (consistent with fully fermenting the sugars etc.) so that when you are drinking the beer the fruit flavor is as fresh as possible. I don't know if puree is different from fresh fruit in this regard, but I suspect not.

Given that your plan is to skip secondary, implying that you're going to package the beer pretty soon, I'm not sure it would make a difference in this case.

 

Why would you add less fruit if adding it early?

 

If anything, I'd expect less flavor/aroma from earlier fruit, since fermentation can blow some of it away.

 

If you go down this road (which seems like a reasonable experiment to me), I would siphon the wort onto the puree and then pitch the yeast. This is probably me worrying about nothing, but pitching yeast directly on puree seems bad for the yeast. (Yeast don't like being in an environment with too much sugar, something about osmotic pressure or something.)

The other thing I'd note is, puree is reputed to be hard to rack your beer off of, and I wonder if it will be worse if used in primary. I guess I have no reason to think so, but if I were you I would be especially careful about moving the fermenter before racking, etc. You're probably going to have to leave a lot of beer behind, unfortunately.

 

I would imagine that yeast can have the same effect on fruit as it seems to have with hop additions. Biotransformations and what not. Split batch it and see...?

 

That's definitely true of brett, as @OldSock describes in his book. Some strains of brett have... damn it, I'm forgetting... glucosidases? so that they release aromatics from things like cherries and coriander by breaking down compounds that would otherwise be scentless. I don't know if that's true of a clean yeast like the one that @Lukass will (presumably) be using.

Speaking of which, @Lukass, have you considered doing this as a 100% brett fermentation? That's roughly what @OldSock did with this batch (results here). A big advantage is that you can get the wort nice and sour, if that's what you want, because brett thrives in low-pH environments.

 

Which aromatics are allegedly released from cherries by brett? All the cherry brett beers I've had or made smell like cherries and brett and they aren't "more cherry" than my Saccharomyces cherry chocolate stout.

Perhaps the brett releases mango aromatics from the cherry and I just can't smell it?

 

You'll have to buy the book to find out!

Or if you really only care about this specific issue, here is the passage I was thinking of (fair use!):

Beta-glucosidase-positive strains are also able to break apart glycosides, odorless molecules where a sugar (in this case glucose) is bonded to a non-carbohydrate aglycone. Glycosides in beer are contributed by spices, fruits, and hops. Once the glucose molecule is removed and fermented, the aromatic aglycone remains. Research focusing on the classic addition of Schaerbeek cherries to Belgian kriek has shown that beta-glucosidase-positive strains are able to release more "important contributors to sour cherry aroma such as benzaldehyde, linalool and eugenol" during refermentation when compared with beta-glucosidase-negative strains.​

But seriously, it's a good book, you should buy it.

Edited to add: Not all brett strains are beta-glucosidase-positive, I don't think. So maybe the strains you're using aren't doing anything for that reason.

 

I will go into verboten ground here and say that some top notch mead makers say that they put the fruit into the primary.
1. The fruit has nutrients for the yeast that honey does not.
2. What ever aromas get blown off get blown off if you add the fruit to the late fermentation or a secondary fermentation.
These guys know of what they speak.

 

Thanks again for your semi-daily American Sour Beers sales pitch with a bonus copyright infringement. I don't need a book to brew sour beer well.

Most of the Schaerbeek Krieks I've had smelt like a wet dog. Based on your copied and pasted text and my personal experience, brett isn't doing anything great for cherries.

 

Despite the glycosides, I think freshness for fruit beers is a much big reason to wait. I like to age my sours out and only add fruit for the last 6-8 weeks. For a Berliner this may not be hugely different than adding in primary, but for a lambic it is. It's also nice to cut down exposure time for some fruits (like raspberries) that can get "seedy" if they spend too long in contact with the beer.

About half the book is readable from the "look-inside" feature on Amazon (including the whole section about glycosides on page 53-54).