Blueberry wine with spontaneous fermentation!

[Rembee]

Since I'm now retired, I decided to knock another one off the ole bucket list.
My wife and I have had a bumper crop of blueberries this year. We are picking an average of 12 lbs a day.
What does not get used up for wine will later become homemade jam.

So now my bucket list journey begins with a blueberry spontaneous fermentation for those of you who are interested.

I started this past Friday (6/4/2021) by picking and smashing 8oz of fresh blueberries. I also picked 6 nice green leaves off the blueberry bushes with no blemishes.
To this I then added warm filtered water, (enough to bring the ph to 3.46 from a 3.14), 4oz of granulated sugar, 1 gram of yeast nutrient.
I poured this mixture into a sanitized 1 quart plastic food container and placed the lid on lightly.
By Saturday afternoon, there were small bubbles around the egdes of the container. This morning there was a full fledged fermentation under way with a solid cap of berries as the pictures show.

This afternoon I put together a 3 gallon blueberry must as per the recipe;

18 lbs of frozen blueberries that were picked last week. Thawed, smashed and placed in a brew bag.
3 gallons of filtered water. (Total volume with water, berries and juice 4 gallons)
Heated up 6 cups of the must juice on the stove and devolved 5 lbs of sugar. Bringing SG to 1.085 from 1.012. (Will check again tomorrow and adjust SG to a 1.090 if needed)
3 tsp of pectic enzyme
1 tsp grape tannin
Adjusted ph to a 3.4 from a 3.08 with potassium bicarbonate.
Holding temperature at 78° with a seed starter pad with thermostat.
Will let pectic enzyme work for 24 hours.
Will check/adjust SG and PH tomorrow if needed.
Will add yeast nutrient and pitch yeast starter tomorrow evening.

 

[Rembee]

My plans are to allow the spontaneous fermentation to take place for 4 to 5 days. Then finish fermentation with 71B Lalvin yeast.

 

[Khristyjeff]

Thanks for sharing your project.
I'm still new to this craft. Are the leaves in the must to cause the spontaneous fermentation ?

 

[Rembee]

The leaves are actually in the starter. They are another source of nutrients for the yeast and also another method of capturing more of the wild yeast.

 

[G259]

I'm just wondering if you even want wild yeast getting a foothold, since you are going to use 71B. Why let a wild (aka random) yeast take over before you pitch your selected yeast. Isn't that why you innoculate your must a day before pitching yeast?

 

[Chuck Rairdan]

Very interesting approach, looking like your batch will have plenty of flavor, color, and character. Just bottled a batch of wild blueberry and it sampled quite well from bulk aging.

 

[Rembee]

I'm just wondering if you even want wild yeast getting a foothold, since you are going to use 71B. Why let a wild (aka random) yeast take over before you pitch your selected yeast. Isn't that why you innoculate your must a day before pitching yeast?

The whole purpose of my experiment is to allow the wild yeast to get a foot hold. According to most studies, wild yeast or indigenous yeast will not be able to ferment past 3 to 4% ABV.
If and when this happens, then I will innoculate with 71B cultured yeast and allow them to finish the fermentation.
The fact that wild yeast take longer to kick in, allows more skin contact time. Thus, greater body, depth of character, and color. Bigger fruit.

A frequent by-product of wild yeast is its unusual or odd odors and flavors. It has been noted by many that the unpredictable aromas and esters imparted by wild yeast is what can add to its complexity, giving it an interesting, sophisticated nature. No two batches of spontaneous fermentation taste the same.

 

[Khristyjeff]

Good explanation.

 

[G259]

Good luck, sounds like a good experiment.

 

[Rembee]

Pitched the wild yeast starter yesterday evening. Starting SG was a 1.088. PH was a 3.4. Temperature 74.8°
Today there is a full on fermentation. SG 1.080.
Stirring and squeezing the brew bag three times a day.

 

[Rembee]

Today (6/9/21) the spontaneous fermentation is still going strong. I'm still stirring and squeezing the brew bag 3 times a day. SG is a 1.056 which puts the ABV right at 4%. I am going to allow the spontaneous fermentation to go a bit longer. Maybe until I see signs of it slowing down. Now these wild yeast have peeked my interest to see how far they can ferment to.

 

[Rembee]

Today, 6/11/21, the spontaneous fermentation is still going strong. The wild yeast have fermented to a SG of 1.016. This puts the ABV right at 9.4%. I have decided not to add 71B cultured yeast and see if the wild yeast will continue to ferment to dry.
Now I'm wondering if I have a great deal of cultured wine yeast hanging out in my kitchen/dinette area from other wines that I have made and/or from my sourdough beard starter.
Tomorrow I will rack off of the blueberry skins and into a 3 gallon carboy and place under an airlock.

 

[Rembee]

Saturday, 6/12/21, after pressing the blueberry skins, I racked into a 3 gallon carboy and a 1 gallon carboy. Placed both carboys under an airlock.
The SG was a 1.004. Wine is still fermenting.
I definitely was not expecting a wild yeast spontaneous fermentation to ferment this far.

Today, Sunday 6/13/21, the SG is at a .998. And the wine is still fermenting. ABV around 11.8%. The wine is very dry with an alcohol tartness. The wine has a very nice blueberry aroma and plenty of body. Nice mouth feel.
I will allow it to ferment out to completion and then check the SG for a final.

 

[Rembee]

Today, 6/16/21 is day 10 of the Blueberry spontaneous fermentation. SG today is at .994.
The wild yeast continue to ferment although it has slowed down some. This goes against everything that I have read on the subject of spontaneous fermentation being able to ferment past 10% ABV.
But then again, there is not much written on exactly how fermentations went and to what finial SG they fermented to prior to culture yeast becoming readily available to the home winemaker.
I would definitely tend to believe that wine was able to be fermented to dry on wild yeast or better known as ambient, indigenous or natural yeast long before they were cultured. All inoculated, selected or cultured yeast are derived from Saccharomyces Cerevisiae which are the yeast strains that are selected from indigenous yeast. These indigenous yeast were and still are very prevalent throughout winers, vineyards and wherever else wine was made.
So am I to believe that within my own blueberry and muscadine vineyard that I have a strong presence of Saccharomyces Cerevisiae yeast strain do to my part of composting my left over fermented skins?
For many years now, every spring, I have been spreading my compost out in my small home vineyard as a fertilizer supplement. This compost contains cultured yeast remnants from every time I make a batch of wine.
Something to ponder on for sure
All in all I am very happy with how this experiment of mine, using a spontaneous fermentation is turning out. I know that I may not be able to produce the exact wine from year to year but so be it. Just maybe this is how it was meant to be!

 

[winemaker81]

This goes against everything that I have read on the subject of spontaneous fermentation being able to ferment past 10% ABV.

Honestly, that makes no sense to me. With wild yeast you're taking luck of the draw, and given that thousands of yeasts exist, getting one that can't get past 10% ABV is probably likely. But since commercial yeasts are specific, cultivated strains, I expect there are wild yeasts that can handle 18% ABV.

My 7th grade American history textbook stated that Nathan Hale (American war of independence hero) died in 1776 and was born in 1789. My teacher pointed this out, with the comment that we should not necessarily believe everything in books.

The compost idea also makes sense. I read an article (last fall?) that spoke of the wood of older wineries being embedded with the local dominant strain of the vineyard, so that even Pasteurized juice ferments with that yeast. Spreading compost containing a commercial yeast -- or even several -- over a period of years might make it (or them) the dominant strain.

 

[Rembee]

Honestly, that makes no sense to me. With wild yeast you're taking luck of the draw, and given that thousands of yeasts exist, getting one that can't get past 10% ABV is probably likely. But since commercial yeasts are specific, cultivated strains, I expect there are wild yeasts that can handle 18% ABV.

I agree whole heartedly @winemaker81. I take what I have read with a grain of salt. This is the main reason that I have been wanting to try spontaneous fermentation. To see what my own results would be and so far I'm impressed! At least now I can say that I have first hand knowledge of what a spontaneous fermentation has done for me. It is the little experiments like this that make our hobby fun. Thinking outside the box to achieve the end result of WINE!
Just to think that some where back in history, my ancestors achieved the same result in making an alcoholic beverage with wild yeast is self rewarding in its own right.

 

[toadie]

Sounds interesting Rembee. I love natural wine but have been scared off trying it mostly from reading on this site. I will say I've had some off tastes that have helped me dial in my routine and I have gained an appreciation for using a known yeast. That said, I like Brett even though it is considered bad by a lot of the wine world. One further point, my raspberries seem to need a more thorough hit of meta compared to plums or currants etc?
I have a renewed appreciation for the work and mostly the risk natural winemakers take. Some years might be award winning and some might be a write off.
Last, are you going to add meta when racking?

Cheers,
Mark

 

[winemaker81]

Me? I'm not adventurous enough to try wild fermentation. I've lost a few batches over the years and am more risk adverse as a result. But it's fun watching others be adventurous.

 

[Rembee]

Last, are you going to add meta when racking?

Yes Mark, I will add the recommended amount of meta for 3 gallons at the next racking and then every 3 months before bottling. I will bulk age at least 9 months before I even think about bottling. I usually bulk age for a year. That way when this batch is ready for bottling we will be picking the next years blueberry crop. We have picked and frozen 52 lbs of blueberries this year and there is still blueberries on the bushes. Now family and friends are picking
I have enough berries left in the freezer for a blend of Noble Muscadines and blueberries that I make. I call it "Musberry wine" lol.

@winemaker81, it's fun being adventurous lol.
I guess the difference is, I have an unlimited amount of blueberries to be adventurous with. If it fails, then I simply chalk it up to experience. Other then my time, it's no harm, no foul lol.

 

[Rembee]

Update:
For those of you who are interested in spontaneous fermentation and for those who wish to follow along in my journey with wild yeast.

Today it has been just over 1 month since I racked into the glass carboys. Fermentation took 10 days to complete. 7 days in the primary and 3 more days after I racked and placed it under an airlock.
I racked both the 3 gallon and the 1 gallon carboys off of the lees and settlement. There was about 1 to 1 1/2 inches of settlement in both. I added the recommended amount of potassium metabisulfite (k-meta) to both and also added American Medium Toasted Oak cubes to both. 12g to the 3 gallon and 4g to the 1 gallon. I will check both in a month to see how far the oaking is progressing.
As I was racking my wife and I both commented on how much the kitchen smelled like blueberries. The aroma coming off the wine as I racked was very pleasant to say the least.
Although the wine is still very green and with a sharp tart flavor from being so dry you could still taste blueberry on the sides and back of the mouth once the alcohol flavor dissipated.
The wine has a very full, almost thick mouth feel once you over come the alcohol tartness.
I am very pleased with the results so far and think that it will only become better and better with time.
I am very glad I took this path of adventure with my home grown blueberries and indigenous yeast that were present amongst them.
I will give another update next month.

Adventurous Me!