Addition of Raspberries to a lambic.

[mrbounds]

Hi All,

Apologies if I have placed this in the wrong category!

I have a lambic that I brewed back in November (my first attempt at such a brew) and I am planning on adding raspberries to this for a Framboise. The beer is still in the primary on the roselare blend and is getting nice and funky looking. I am getting itchy to add the berries into the fermenter but have a couple of questions:
1: How many lbs of fresh raspberries do I need to add in order for a framboise taste?
2: Is 17 weeks or so a good point in time to add?
3: Should I think about replacing my airlock with a blow off once the fruit has gone in?

Thanks in advance for any advice!

[nateo]

I don't have a definitive answer for you, but maybe a couple of things to think about. The acid in the fruit will lower the acid in your wort. How much will depend on how much fruit you add. But yeast gets grumpy if the pH drops below 4, and really grumpy under 3.

Depending on how much the Roselare blend has dropped the pH, you might need to rely on the Brett and bugs to ferment any sugars the raspberries add. I don't have any idea how long that would take.

If it were me, I would wait until the lambic is finished, then ferment the raspberries separately, maybe with a little fresh wort for nutrition, then blend the two to taste. I think you would get a fresher raspberry taste. It's also possible I have no idea what I'm talking about.

[dimik]

I'd say let it sit longer, like 6-12 months and then rack on raspberries and let sit for another 3-6 months. Then bottle.

[jmcamerlengo]

I'd say let it sit longer, like 6-12 months and then rack on raspberries and let sit for another 3-6 months. Then bottle.

This is my plan. 12 months with the bugs then another 3 months with fruit. Using 10 lbs of cherries in mine! for 5 gallons.

[morticaixavier]

As I understand the traditional process you would take a barrel and fill it with raspberries. then rack the beer on top of the fruit. lots of fruit. lots. like 2 lbs per gallon. it will spark a secondary fermentation and a blow off might not be a bad idea. you should wait till it is done, i.e. the gravity is no longer dropping.

on the pH front, I wouldn't worry about it. traditional lambic brewers don't. the brett and bugs are doing most of the work and they actully prefer a fairly low pH environment.