Sour ale - when should I add the fruit?

I would wait at least a year. This will allow the primary yeast to die off, otherwise the sugar from the fruit will mostly just increase the alcohol instead of sourness. I have heard some say aging for 3 months is best for fruit flavor.

 

The later the better. If you are doing 18 months aging, I would wait until 15 months until adding the fruit. The fruit will fade with time just like in a standard fruit beer, the longer you age it on the fruit the less fruit character you will get in the end product.

 

Yes, 3 months before packaging.

 

When should you add the fruit to a Sour Ale? Personally, I would say never But that's not helpful.

It depends. You want the fruit to age proportionally with the rest of the beer. Flavors need time to meld. Too short a time and they'll taste too fresh. Too long and you'll lose too much of the cherries. A fixed 'three months' may be too early for a beer that will be aged for three months, or too late for a beer that will be aged for ten years. I would suggest adding them at about 90% of its aging time. IOW, if you're going to age it for a year, then add the cherries about 5 weeks before serving. If you're aging it for 18 months, then about 2 months.

 

I should have qualified my advice by saying that I've not done A-B comparisons on different techniques, only that this made sense, I do it routinely, and it works great! I've also had discussions with some of the more experienced members of my brewclub, and the consensus is that this is a sound practice.

Regarding your predicament (cherries arriving tomorrow), you'll be fine. The primary 'damage' from freezing, such as it is, is that cell walls rupture, releasing water, resulting in a product that is not quite what it was before freezing. But this is primarily a texture issue. (This is hideously evident with fish. Less so, but not insignificantly with meats like beef, pork, and chicken, for example). In this case, that's largely irrelevant - you're looking for sugars and the good stuff that makes a cherry taste like a cherry. Texture is not an issue.

That said, package them properly for the freezer! FoodSaver is an insanely valuable tool for things like this.

 

Add fruit when the beer is done. I never plan on fruiting a beer or set a timeline on my sours. I let taste tell me what to do and when to do it.

 

To thine own mouth be true.

 

Agreed. Fruit should be added once an appropriate level of acid/funk has been achieved in the beer. I go with 20# of IQF fruit for a 5 gallon batch. Primary with Belgian Golden. Secondary with Lacto, Brett, and wood chips that have been steamed and inoculated. Condition until acid/funk flavors develops to one's liking (in my case this has occurred anywhere from 14-18 months for me over the last three batches completed). Rack beer onto fruit that has been allowed to thaw to room temperature in a 6.5 gallon carboy. Condition for one month before sampling, sample once every two/three weeks until the beer is to your liking (in my case this has occurred between 10-12 weeks), rack off fruit, then package for consumption. You may need to filter fruit debris from beer prior to being bottled, and you will lose some volume to the fruit. I bottle all my sours so that I can sample over time. I use locally grown blueberries, freeze them in a single layer on sheet trays, then bag them for storage prior to use. The use of fresh, unfrozen berries would introduce unknown wild yeasts and bacteria that adds a variable that I have not been willing to accept into the equation up until this point. I highly recommend Jeff Sparrow's Wild Brews.

 

Do these 'unknown wild yeasts and bacteria' somehow become less undesirable after freezing?

 

Or eat them and buy more in 15 months.

 

To my understanding, yes, freezing slows them down to the point where they are not able to compete with the remaining brett and lacto in the beer, at least within the time period that I have aged the beer on the fruit. In Wild Brews Sparrow states, "The traditional brewer [of Lambic/Gueze and Flanders acid ales] generally allows the beer and fruit to ferment from six to nine months" (230). To my knowledge, traditional brewers do not freeze the fruit before adding to their beer, but they also have much more knowledge/experience making fruited Lambics/acid ales than I, and are confident that the flavors contributed by any wild yeast or bacteria left on the skin of the fruit will not have too much of a negative impact on the beer. I use cultures of Brett and Lacto from White Labs to inoculate my homebrewed acid ales, and as I am unsure as to what wild yeast and bacteria live in my area (the blueberries are grown on a farm <5 miles from my house), I am reluctant to intentionally introduce them to my beer in anything other than the lowest concentration possible.

 

My understanding is that, in general, freezing stops the bacterias' progress only while it's frozen. Once thawed, it restarts exactly where it left off. There may be some lag time before things become a problem, and I'll defer to the experts on that point (I judged some wild stuff with Jeff a few years ago and he definitely knows a thing or two more about this topic than I do).

 

Why not find out? Take them there blueberries, put a handful into 1L of 1.020 wort with 1/3 apple juice 2/3 water for your liquid, and let them sit for 2 weeks. Step it up to 1L of 1.040 wort. Then 2L, pitch it into a 5 gallon batch of Lambic wort, and let her go for one year, no dregs, no WLP cultures. See what you have. I fermented my first Lambic with yeast I cultured off blackberries growing over the fence into my yard from the neighbor's house. Took it down to 1.006 in 3 weeks, fruity, light acids, lots of tropical fruit. Had some last night at almost 2 years old now, soft acids, lots of fruit, light funk (and I added lots of dregs to that batch over the year it fermented).

 

I've added some immediately at secondary, after a 3-4 week primary ferment, though they were usually dried fruit. Left the beer on them until packaging (6 - 18 months). Also have "finished" a sour after a secondary for ~ 1 year, before racking onto fruit (fresh, then frozen) for 3-4 months.