Developing a unique house yeast using Open Fermentation, ala Jolly Pumpkin

Does anyone know more about this, or have any advice/critiques on the technical aspects?

I am attempting to develop my own unique yeast culture in the Franco-Belgian tradition, using open fermentation. This isn't a spontaneous fermentation because I am not inoculating my wort with strictly airborne yeast (like a true Lambic) but rather with the yeast cake from the previous batch.

However, every batch I brew I am doing an open fermentation. So I am simply putting cheese cloth over the carboy mouth to keep out flies, and leaving it by the open window to allow the various native yeasts to co-mingle. The original pure (commercial) strain I used to start the first beer was a Belgian Witbier yeast from WYeast, but I am now finishing the second batch with this culture.

So far everything has turned out fine, and I imagine the beers will slowly sour as they age. As I re-use it from batch to batch, I imagine the culture will evolve to more accurately represent the "terrior" of the place where I brew and the wild native yeasts already present in the air. We'll see how that goes.

I am curious if anyone else has experience doing this?

you don't live down wind of the dump, highway, or water treatment plant do you?

TelemarkBrew said:

you don't live down wind of the dump, highway, or water treatment plant do you?

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Nope. I do live in the city (ideally this should be done in the country by organic orchards and farms...) but its a fairly quite neighborhood with a lot of backyard gardens and a nice park down the street.

nice, sounds like a cool expirement.

I'm crossing my fingers. Already have run into a few technical issues.

The first was bottle conditioning. I had allowed the first batch to secondary and tertiary for quite a while (washing and saving the yeast cake after each racking), so there wasn't much primary yeast left in the beer by the time I was ready to bottle. The reason I waited so long was because I wanted to give the wild yeasts and lactos some time to age and sour in bulk before I split them off into bottles.

Well, when I was ready to bottle, I had already used all the saved primary yeast to pitch into my second batch, so I had to rack that batch mid-fermentation and wash out some of its yeast. Because I was in a rush to bottle (for logistical reasons) I didn't give that stolen yeast cake enough time to settle and compact. I also didn't want to add too much because the second beer has some spices and herbs I was trying not to get the flavors of into the beer I was bottling.

To make a long story short, I probably didn't add enough primary yeast for a strong bottle conditioning. I did add some DME, though not as much as you normally would with a pure yeast strain because I'm assuming some of the wild yeasts and lactos will attenuate the beer very highly as it ages.

Right now I am storing the bottles in my warm upstairs closet and shaking them everyday to try to stimulate bottle-conditioning. We'll see how that goes after a couple of weeks. I may open a bottle in a couple of days to see if its working.

The second issue I forsee is the accumulation of trub and dead yeast in my yeast culture. I have read the sticky thread on yeast washing, which seems straight forward enough, but I am concerned about collecting too much junk and dead yeast over time, thus leading to bad off flavors like autolysis, or hops, spices, flavorings, etc... from previous beers being carried into subsequent ones.

One idea I had to take care of the spices/flavorings being carried over, is to double-wash the yeast cake. One it has settled out in the fridge and compacted, I decant the top liquid and add fresh sterile, cold water to further dilute any flavors that may be present. But this still doesn't solve the problem of accumulating dead yeast cells that may lead to autolysis off-flavors.

Any suggestions?

I wouldn't worry about it to much, a lot of people leave these in the primary for the whole year+ fermentation, gives the buggies something to feed on (assuming you are getting some brett/lacto/pedio in there to sour it).

Check out this thread. the OP disappeared, but it's an interesting read.


https://www.homebrewtalk.com/f13/ambient-spontaneous-fermentation-43888/

brewmonger said:

The second issue I forsee is the accumulation of trub and dead yeast in my yeast culture. I have read the sticky thread on yeast washing, which seems straight forward enough, but I am concerned about collecting too much junk and dead yeast over time, thus leading to bad off flavors like autolysis, or hops, spices, flavorings, etc... from previous beers being carried into subsequent ones.

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Add some oak chips, these will be colonize by brett, pedio, etc and then you can use these for innoculation of further brews

for your innoculation I would try it when its quite a bit cooler(october, November?), so that there arent any flies, and some of the nasties that prefer warmer temps wont be floating around in the air, wild beers were traditionally brewed in the cooler fall months to capture the correct wild bacteria, and to provide a cooler ferm temp during the winter to minimize acid/vinegar production

from my understanding, the best yeast is from top cropping and not the crap at the bottom. Bottom yeast can only be used 5ish times while top cropped yeast can be used infinite (technically)

http://www.wyeastlab.com/com-yeast-harvest.cfm

Congrats on the zombie