Sour/Acidity Adjustment on Flanders Red

[Sublime8365]

Not sure if this belongs in the Lambic/Wild forum but this one is much more active so starting here..

So I brewed the following Flanders Red recipe: https://www.homebrewtalk.com/forum/threads/rodenbach-clone.224122/#post-3463464

Brew day hit 1.060, was in primary for about 3 weeks and took it down to 1.011. Transferred to secondary and it currently sits around 1.003 after about 15 months after transferring. The sourness is very very subtle and not to my liking. I took a pH measurement and it's ~4.2. Note: It's been sitting at serving temps for about 4 months so it probably only spent about a year at ambient temp. (this is probably my first mistake and not even really sure why I put it in the fridge). The beer is not carbed.

I've read about adding maltodextrin to sour beers to help along the souring process. Is that recommended? How much should I be adding? (I'm really not worried about the beer getting too sour so if adding incrementally is going to take another year then I'd rather over-shoot on sourness). Should I add another pack of Wyeast 3763? Any help is really appreciated.

 

[RPh_Guy]

At that hopping rate with a first generation commercial culture, expect it to take up to 18 months at room temperature (over 65°F) to sour.

Yes, I would warm it back up and add some maltodextrin. IIRC, @cactusgarrett uses 8-16oz in the recipe.
Dissolve the MD in hot water before adding, otherwise it forms a gooey glob.

Your other option is to add live dregs from commercial sour beers. Their lactic acid bacteria are MUCH more hop-tolerant than the strains from yeast labs. The Brett from the dregs may change the beer flavor (probably for the better, but be aware), and may attenuate further.

 

[cactusgarrett]

If you're down to 1.003 already, you need to feed any present bugs or one you add. I think just dregs alone won't work, and it's clear the bugs present aren't going to do anything further. Maltodextrin is perfect for that.

 

[Sublime8365]

If you're down to 1.003 already, you need to feed any present bugs or one you add. I think just dregs alone won't work, and it's clear the bugs present aren't going to do anything further. Maltodextrin is perfect for that.

Would you add the full 1 lb like your recipe calls for? Also, if I'm trying to add from dregs, do you usually use a starter for sour dregs? I haven't harvested from a bottle before, most methods I read suggest creating a starter but the Wyeast website says Roeselare blend (which I used in the original recipe and from what I've read is from Rodenbach, which I'll likely use for the bottle dregs) should not be propagated in order to maintain a proper proportion of the various cultures in the blend - would this same rule apply to bottle dregs or would the benefits of growing the cell count outweigh any negatives considered in the wyeast website?

 

[cactusgarrett]

I say go for the full pound, but you're going to have to way for the brett and bugs to work on it. I wouldn't do a starter - there's too much room for error in that and it'd throw off the ratio of all the goodies living in there, as you mentioned. Just pitch as many as you like that you can find and wait. Only time I consider doing a starter with dregs is when you're intending on doing the bulk of fermentation with the sample.

 

[RPh_Guy]

I make a small starter (100-150mL) from bottle dregs to see what's alive. I can easily smell whether I get Brett and/or lactic acid bacteria. I've had a couple that didn't grow anything.

I recommend to add light hops to the starter wort. Just toss in a pellet. This helps preserve the hop tolerance of the bacteria.

The bottle dregs don't have a carefully engineered ratio of various yeast and bacteria types to preserve like commercial cultures, so there's no benefit to avoiding a starter in my opinion.

Maltodextrin should definitely help whether or not you use dregs.

 

[cactusgarrett]

Great ideas! I was trying to think of a way to get the bugs involved, but with an assumed already established (recipe dictated) IBU of 16, I wasn't sure how that could be done. @RPh_Guy , you think conditioning the bugs with IBU in a starter could get them to sour in the presence of >5-10 IBU?

 

[RPh_Guy]

I've seen two approaches to actually increase hop tolerance of LAB:
1. Steadily increase hop presence in successive starters, like 5-10% every couple days.
2. Use an agar plate growth medium with a hop gradient.
MTF wiki covers both of these processes.
I wish there were an easier way to do this.... Maybe make a starter with wort+lactose+nutrient as hoppy as you want and then keep adding wild Lacto and/or dregs to it until at least one strain sours it? Could work, but still kind of involved unless you get lucky.

I haven't really gone through the process of trying to increase hop tolerance -- partly because it's easy enough to add bitterness after souring, and partly because I'm not sure I want to generate super hop-tolerant Lacto strains floating around my house.

Some LAB in sour dregs (probably Pedio) are already hop tolerant to whatever level of hops were used in that beer, so it's definitely fine to add dregs directly to the fermenter (cell count doesnt matter). I just prefer to make a starter (1) to see what's alive and (2) so I can save that culture separately to use in other projects.

When LAB are propagated in unhopped media, they typically lose hop tolerance (ahem, yeast lab bacterial cultures). By adding hops to the bottle dregs starter I'm just hoping to preserve the tolerance they already have, rather than increase it.