[wmbolling]

So I brewed my first sour, a recipe for a "Sour Brown Ale" in January, and curiosity got the better of me last night- it has now been 10 months and it was time to see what this sucker tasted like. I pulled a small amount off and to my surprise it was nowhere near as sour as I was expecting.

It was fermented with a Belgian strain for primary, and then after about 6-8 weeks I racked it onto 3 lbs of raspberry puree, some medium toast french oak spirals that were soaked in Johnnie Walker Red, and I added Brett, Pedio & Lacto. It's been sitting there ever since- taunting me from the corner of my bedroom to prematurely drink it.

It is much more malty than I wanted. But I think this could be a good thing if I can get more tart character to it- but how? You can definitely tell that there is a slightly acidic after taste, but I want to be puckering up like I just had a Thanksgiving dinner composed entirely of Warheads. How can I sour this thing up? Here are the options I am considering:

-Do nothing- leave it to grow old and sour peacefully. It is sitting at room temp (~68).
-Add heat: Could those bugs speed up the process if I wrapped my carboy with a low intensity heating blanket or something?
-Rack it onto some strawberries to add some more sugar for the bugs to work on- I am afraid they are out of food.
-Chalk this up as a learning experience

Another factor is that this thing has turned out with a WAY higher ABV than I anticipated. I was shooting for ~8%, but with the raspberry puree, it is currently sitting at like 14%. Could the high ABV cause the Lacto & Pedio to be inactive?

Anyone with experience who would like to lend some advice from a similar situation would be appreciated!

[tschmidlin]

How are you doing your ABV calculation?  Are you sure it is accurate?

14% ABV would definitely inhibit the bacteria.

[wmbolling]

I added the OG with the estimated additional sugars from the raspberry addition- OG was around 1.065 and according to the label raspberry puree, I needed to add an additional 1.050-1.057, giving me a total of (potentially) 1.122. The FG is 1.012.

Even though the wort had finished fermenting before I added the raspberries, I was under the impression that I could simply add the additional sugars from the fruit addition to my OG to get an accurate measurement of the total.

[kylekohlmorgen]

Be patient!

8% ABV is on the high end for lacto's tolerance, so you are relying on pedio for the bulk of acid production. Pedio is SLOW and always late to the party. I don't expect any pedio activity for at least 8 months on an initial pitch, and a year wouldn't be unheard of.

Pedio doesn't do oxygen, so fight the urge to sample, rack the beer, or move the carboy around (unless you need to hide it so it stops taunting you). Sample again in 3-4 months. If there's no increase in acidity after that, you might consider blending/repitching/etc.

Also: The raspberry puree wont bump your ABV from 8% to 14%. Read Fred's post here:
http://www.homebrewersassociation.org/forum/index.php?topic=12133.0

[tschmidlin]

I added the OG with the estimated additional sugars from the raspberry addition- OG was around 1.065 and according to the label raspberry puree, I needed to add an additional 1.050-1.057, giving me a total of (potentially) 1.122. The FG is 1.012.

Even though the wort had finished fermenting before I added the raspberries, I was under the impression that I could simply add the additional sugars from the fruit addition to my OG to get an accurate measurement of the total.

Not exactly - you have to take the volumes into account. 

(OG1xV1 + OG2xV2) / (V1+V2) = OG

In other words, the OG of your beer times the volume (1.065 @ 5 gallons = 65x5 = 325 points) plus the sugar from your fruit (1.053 @ 1 gallon (?) = 53x1 = 53 points) divided by the total volume ((325+53)/6=63, so your beer had an "OG" of 1.063 and is now at 1.012 so it is 6.7% ABV.  Obviously you need to use your real numbers, I took some guesses.

But either way, the yeast may have started a renewed fermentation when you added the fruit.  You might consider boiling 1/2 lb of maltodextrine in a couple of cups of water to dissolve it, then add that to the fermenter.  The yeast won't be able to break it down, but the bugs will and that will give you an acidity bump.

[garc_mall]

I added the OG with the estimated additional sugars from the raspberry addition- OG was around 1.065 and according to the label raspberry puree, I needed to add an additional 1.050-1.057, giving me a total of (potentially) 1.122. The FG is 1.012.

Even though the wort had finished fermenting before I added the raspberries, I was under the impression that I could simply add the additional sugars from the fruit addition to my OG to get an accurate measurement of the total.

Not exactly - you have to take the volumes into account. 

(OG1xV1 + OG2xV2) / (V1+V2) = OG

In other words, the OG of your beer times the volume (1.065 @ 5 gallons = 65x5 = 325 points) plus the sugar from your fruit (1.053 @ 1 gallon (?) = 53x1 = 53 points) divided by the total volume ((325+53)/6=63, so your beer had an "OG" of 1.063 and is now at 1.012 so it is 6.7% ABV.  Obviously you need to use your real numbers, I took some guesses.

But either way, the yeast may have started a renewed fermentation when you added the fruit.  You might consider boiling 1/2 lb of maltodextrine in a couple of cups of water to dissolve it, then add that to the fermenter.  The yeast won't be able to break it down, but the bugs will and that will give you an acidity bump.

I used flour rather than maltodextrine in my flanders red, and it worked really well.

[tschmidlin]

I used flour rather than maltodextrine in my flanders red, and it worked really well.

Do you still have any?  I'd like to try it.

[garc_mall]

I used flour rather than maltodextrine in my flanders red, and it worked really well.

Do you still have any?  I'd like to try it.

I have 5 gallons, because I have been traveling too much to get it into a keg.

[wmbolling]

Tom- Thanks for breaking that down for me! This was my first time experimenting with adding any pureed fruit to my beer, so there is always a learning experience. I appreciate it. I like the idea of boiling/adding the maltodextrine and will probably do so this weekend.

So no one suggests adding heat to try and boost the production of the Lacto & Pedio?

[kylekohlmorgen]

You might consider boiling 1/2 lb of maltodextrine in a couple of cups of water to dissolve it, then add that to the fermenter.  The yeast won't be able to break it down, but the bugs will and that will give you an acidity bump.

Can lactic acid bacteria break down dextrins? I always thought brett broke down the complex stuff, but lactic acid was always fermented from glucose.

My copy of Wild Brews is packed away, else I'd look when I got home.

[tschmidlin]

You might consider boiling 1/2 lb of maltodextrine in a couple of cups of water to dissolve it, then add that to the fermenter.  The yeast won't be able to break it down, but the bugs will and that will give you an acidity bump.

Can lactic acid bacteria break down dextrins? I always thought brett broke down the complex stuff, but lactic acid was always fermented from glucose.

My copy of Wild Brews is packed away, else I'd look when I got home.

Lactobacillus can use a wide range of carbon sources, but it is highly strain dependent and I don't know what strain of lactobacillus we're dealing with.  Presumably lactobacillus delbrueckii?  In any case, published lab tests show that many strains of lactobacillus can use dextrin as a carbon source.

But to be honest, I was lumping brett in with the bugs.  I should have been clear about that since it could easily have been lumped in with the yeast.

[tschmidlin]

Tom- Thanks for breaking that down for me! This was my first time experimenting with adding any pureed fruit to my beer, so there is always a learning experience. I appreciate it. I like the idea of boiling/adding the maltodextrine and will probably do so this weekend.

So no one suggests adding heat to try and boost the production of the Lacto & Pedio?

I think heat would be a bad thing at this point.

[kylekohlmorgen]

Lactobacillus can use a wide range of carbon sources, but it is highly strain dependent and I don't know what strain of lactobacillus we're dealing with.  Presumably lactobacillus delbrueckii?  In any case, published lab tests show that many strains of lactobacillus can use dextrin as a carbon source...

Neat!

In any case - I would still leave 'er be for awhile.

[reverseapachemaster]

I seem to recall that pedio can also break down dextrins although much slower than brett or lacto. Brett might be the most efficient at tearing up dextrins but once the dextrins are broken down the shorter chain sugars would be available for the bacteria to consume to produce acid.

[tschmidlin]

I seem to recall that pedio can also break down dextrins although much slower than brett or lacto. Brett might be the most efficient at tearing up dextrins but once the dextrins are broken down the shorter chain sugars would be available for the bacteria to consume to produce acid.

Pedio and lacto are morphologically similar and strains have been reclassified even recently.  But within each classification there is variation, so I would say maybe the pedio can break it down and maybe it can't.

You may be right about the brett being most efficient, but I haven't seen any data on that.

For your entertainment, here is a 2009 article reclassifying pedio dextrinicus as lacto dextrinicus
http://ijs.sgmjournals.org/content/59/3/615.full