[James K]

I have made many starters before but have never tried to build up dregs until last night. Maybe not enough time has passed.

I used a pint of water and a half cup of dme, boiled and cooled, and added some yeast nutrient before I pitched 3 dregs from different bottles. I was trying to build a sour culture that is a mix of 3711 and Brett b. And two bottles that used 3711 and white labs Belgian sour mix. When I poured the dregs out of the bottle the solution was brown.  Two of the bottles have been sitting around quite a while. I let this starter sit on a stir plate for a while and it’s been sitting over night but no noticeable activity.

Is my yeast dead? Not enough time passed?
There is no white layer of yeast at the bottle of my flask, it’s more beige color, and not very thick.

I have more of the same bottles if fresh dregs are required, I would like to try a mixed fermentation sour soon though.
Any advice on building and using dregs would be helpful.

[Bob357]

If you've done plenty of starters  on a stir plate before, I assume you aren't looking for krausen, but rather a milkiness in the starter. The dregs from 3 bottles isn't a bunch of yeast, so be patient. Usually, you would start with a very small amount of wort and use several starters to gradually build to a pitchable count. Give it a day or so and then take a gravity reading to see if it is, or has, fermented.

[Joe Sr.]

Good advice above. Typically you want to start dregs with very little weak wort. I start in the bottle and then step to a flask after a day or so. If you don't get anything going start again with the other bottles.


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[James K]

If you've done plenty of starters  on a stir plate before, I assume you aren't looking for krausen, but rather a milkiness in the starter. The dregs from 3 bottles isn't a bunch of yeast, so be patient. Usually, you would start with a very small amount of wort and use several starters to gradually build to a pitchable count. Give it a day or so and then take a gravity reading to see if it is, or has, fermented.

What is a small amount of wort, or a “weak wort”?
I agree about building up, I’ve never done this before and am just seeing what I get. The starter does look larger than it did this morning. Still not a fresh color like I’ve seen but it’s growing.
The starter also has bacteria from the sours. In a day or two should I make more wort to help growth?

[oginme]

I have not built up yeast from dregs, but I do often build up a yeast pitch from an agar plate.  When I start, I pick off 8 to 10 good colonies (usually around a million cells per colony) and transfer this into about 20 ml to 30 ml of a 1.020 to 1.025 gravity wort.  This 'wakes' the cells up from dormancy.  About 16 to 24 hours later, I will pitch the initial 'starter' into 200 ml to 250 ml of a standard 1.036 to 1.040 gravity starter wort.  I think this approach is the one to which Bob357 is referring: low gravity, low volume start, then ramping up to a larger starter volume at standard gravity.

[James K]

I have not built up yeast from dregs, but I do often build up a yeast pitch from an agar plate.  When I start, I pick off 8 to 10 good colonies (usually around a million cells per colony) and transfer this into about 20 ml to 30 ml of a 1.020 to 1.025 gravity wort.  This 'wakes' the cells up from dormancy.  About 16 to 24 hours later, I will pitch the initial 'starter' into 200 ml to 250 ml of a standard 1.036 to 1.040 gravity starter wort.  I think this approach is the one to which Bob357 is referring: low gravity, low volume start, then ramping up to a larger starter volume at standard gravity.

I’ll have to try this in the future, I have no experience with agar plates or the colonies of yeast themselves.
For now I am about to give the yeast some more food.  The cake on the bottom looks to have grown so will see what happens when more food is introduced. Hopefully a healthier looking cake develops.

Are there significant downsides in the method I just did?

[erockrph]

This is cut-and-paste from an old post of mine, so apologies if something is missing here, but here's the procedure I follow for bottle dregs:

For the initial step, I like to do it in the bottle instead of pouring the dregs off. Transfers are the times where you run the biggest risk of contamination, so I like to make sure the culture is woken up a bit before transferring out. Sanitize the bottle and bottle opener before opening. Then sanitize the neck/lip of the bottle before pouring the beer. I like to leave about 1/2 inch of beer in the bottle, plus the dregs. this way you get any yeast that is still in suspension and not just the flocced out dregs.

I then use a sanitized funnel to add about 1/2-1 inch of 1.030ish wort. Once diluted with the remaining beer, this gives you a nice low OG of about 1.020. This is less stressful to the yeast than the typical 1.040ish starter wort we typically use. Then I cover with foil (for non-sours) or add a small stopper and airlock (for sours). I usually give the first step about 7-10 days to give the yeast plenty of time to wake up and do their thing.

From there, the general rule for stepping up a starter is a tenfold increase each step. So step two is maybe 200 mL or so of 1.035 wort, and then that can go into a normal 2-liter starter. Use your nose to tell you whether there are any problems, and taste your larger starters to ensure that you didn't pick up any contamination along the way.

[James K]

This is cut-and-paste from an old post of mine, so apologies if something is missing here, but here's the procedure I follow for bottle dregs:

For the initial step, I like to do it in the bottle instead of pouring the dregs off. Transfers are the times where you run the biggest risk of contamination, so I like to make sure the culture is woken up a bit before transferring out. Sanitize the bottle and bottle opener before opening. Then sanitize the neck/lip of the bottle before pouring the beer. I like to leave about 1/2 inch of beer in the bottle, plus the dregs. this way you get any yeast that is still in suspension and not just the flocced out dregs.

I then use a sanitized funnel to add about 1/2-1 inch of 1.030ish wort. Once diluted with the remaining beer, this gives you a nice low OG of about 1.020. This is less stressful to the yeast than the typical 1.040ish starter wort we typically use. Then I cover with foil (for non-sours) or add a small stopper and airlock (for sours). I usually give the first step about 7-10 days to give the yeast plenty of time to wake up and do their thing.

From there, the general rule for stepping up a starter is a tenfold increase each step. So step two is maybe 200 mL or so of 1.035 wort, and then that can go into a normal 2-liter starter. Use your nose to tell you whether there are any problems, and taste your larger starters to ensure that you didn't pick up any contamination along the way.

I’ll have to try that, pretty interesting but probably likely something I would try on a commercial bottle I enjoyed. Why foil for non sours and an airlock for sours though? 

[erockrph]

This is cut-and-paste from an old post of mine, so apologies if something is missing here, but here's the procedure I follow for bottle dregs:

For the initial step, I like to do it in the bottle instead of pouring the dregs off. Transfers are the times where you run the biggest risk of contamination, so I like to make sure the culture is woken up a bit before transferring out. Sanitize the bottle and bottle opener before opening. Then sanitize the neck/lip of the bottle before pouring the beer. I like to leave about 1/2 inch of beer in the bottle, plus the dregs. this way you get any yeast that is still in suspension and not just the flocced out dregs.

I then use a sanitized funnel to add about 1/2-1 inch of 1.030ish wort. Once diluted with the remaining beer, this gives you a nice low OG of about 1.020. This is less stressful to the yeast than the typical 1.040ish starter wort we typically use. Then I cover with foil (for non-sours) or add a small stopper and airlock (for sours). I usually give the first step about 7-10 days to give the yeast plenty of time to wake up and do their thing.

From there, the general rule for stepping up a starter is a tenfold increase each step. So step two is maybe 200 mL or so of 1.035 wort, and then that can go into a normal 2-liter starter. Use your nose to tell you whether there are any problems, and taste your larger starters to ensure that you didn't pick up any contamination along the way.

I’ll have to try that, pretty interesting but probably likely something I would try on a commercial bottle I enjoyed. Why foil for non sours and an airlock for sours though?

Sours need an airlock because the dregs likely include some Acetobacter, which grows better with oxygen exposure. Non-sours don't need the airlock, since I don't really care if I oxidize that small amount of wort. It's merely a matter of simplicity in that case.

[Robert]

When possible (apparently not with sour?) best practice for starters is to loosely cover with foil (or sterile cotton) precisely because it allows oxygen ingress, resulting in better growth.

[James K]

When possible (apparently not with sour?) best practice for starters is to loosely cover with foil (or sterile cotton) precisely because it allows oxygen ingress, resulting in better growth.

I used an airlock to build these up, normally I use a sanitized sponge. But I usually make a starter in a day before the brew.  Those dregs are working nice now, pellicle is forming, had this huge bubble the other day.

The bug strains I put in the beer say temps in the 80s but right now it’s low, I fermented at 75-80. I needed the temp controller for a neipa. When that is done I might ramp it back up. Not sure. I was warmed about off flavors at high temps.

[ASLO]

All good advice. Some more good information here:

http://www.milkthefunk.com/wiki/Commercial_Sour_Beer_Dregs_Inoculation

They recommend covering with foil to allow oxygen ingress. Something to consider. As was mentioned, don't forget to sanitize the mouth of the bottle with flame or sanitizer. I just had some Orval dregs go south on me the other day after forgetting to sanitize the bottle. Smelling and tasting your starter liquid each step of the way will help you determine if you've picked up any unwanted yeast or bacteria. Mine tasted like dirty diapers and some used band aides.