Is my fruit fermenting?

[catman]

I am brewing a catharina sour that I’ve made a few times before. I usually make and pasteurize my own raspberry purée from frozen raspberries and it is pretty reliably good. This time I made a split batch—half of the beer went on raspberry and half on a canned apricot puree that I bought from my local homebrew shop.

With the raspberries, I’m used to seeing a line of yeast descend slowly through the fruit over a few days from racking... or at least that’s what I think is happening as the fruit discolors somewhat from the top down. And that’s happened in the two weeks that the beer has been on the raspberries (see attached photo with what was formerly very red raspberry purée on the bottom).

But the apricot purée isn’t doing the same thing (see attached photo) and honestly looks about the same now as it did two weeks ago when I racked on to it. The line of discoloration doesn’t seem to be descending through the purée. Does this mean it’s not fermenting? Fermenting very slowly? Something else?

Thanks!

 

[Jag75]

I think it has to do with the color of the fruit. When I brew blueberry sours the berries loose their color . I made an apricot/peach ale and it looked like yours . All looks fine to me.

 

[catman]

I think it has to do with the color of the fruit. When I brew blueberry sours the berries loose their color . I made an apricot/peach ale and it looked like yours . All looks fine to me.

Thanks. Is there any way to get a sense visually or whether the fermentation of the fruit is moving along?

 

[VikeMan]

Thanks. Is there any way to get a sense visually or whether the fermentation of the fruit is moving along?

Do/did you see bubbles in your airlock? It's not a very good quantitative indicator, but assuming a non-leaky fermenter, it can be a good qualitative one.

 

[catman]

Do/did you see bubbles in your airlock? It's not a very good quantitative indicator, but assuming a non-leaky fermenter, it can be a good qualitative one.

I find that that’s not a particularly good indicator for a secondary fruit fermentation—it’s usually not so vigorous that the frequency of bubbling is much distinguishable from bubbling due to off-gassing or temperature changes

 

[Jag75]

Thanks. Is there any way to get a sense visually or whether the fermentation of the fruit is moving along?

Only true way is to check the gravity. I bottle my sours so I'm kind of finicky with these. Visually you should see some bubbles in the beer . I leave the beer on the fruit for at least 1 week .

 

[VikeMan]

I find that that’s not a particularly good indicator for a secondary fruit fermentation—it’s usually not so vigorous that the frequency of bubbling is much distinguishable from bubbling due to off-gassing or temperature changes

If your bubbling during secondary on fruit is indistinguishable from the bubbling from off-gassing, I'd guess you might have a bit of a leak somewhere. When I do fruit beers (even sours, where the "clean" fermentation is slowed) with airlocks, I can easily tell the difference. It's a true secondary fermentation.