I finally tried the James Bond method. I had about 120 ml of dense slurry of WLP 029 3rd. generation that was a bit older than two months. I usually pitch the slurry directly from the fridge, but it takes up to 36 hours to form a layer of krausen and start blowing off CO2. I made a 1 L starter using this method, and it took off like a rocket in less than 8 hours. Amazing. I’ll never go back if this is what I get from this method. Thanks, Mark!
Whew!
Nerve racking trying something new. I finally gave the procedure a try. 1 L, 1 two month old smack pack. Pack was expanded. I was expecting at least twelve hours to high krausen. Sixteen hours later it appeared high krausen had taken place hours ago. It probably occurred around the seven hour mark. Is this possible? There was a nice slurry at the bottom of the flask like it had dropped out and was going dormant. Does the age or viability have this kind of effect on high krausen time? I did use an Erlenmeyer if that makes a difference. The house temp was around 65.
I think the expected peak of krausen occurs sometime around 8 hours.
The other thing I see that you did was to use an Erlenmeyer flask. I think you’re supposed to use a one gallon jug so that you can shake the starter wort so hard that it completely turns to foam. You need room enough to create a 4 to 1 ratio of foam to wort.
Im 6 batches into this method, 5 with <1 month old 1056 and 1 with 2 month old 1257. All of these have reached HK at around 8 hrs. I use erlenmeyers but I dont shake, I oxygenate. I dont think that part matters a whole bunch. Though clearly if you are shaking, having a bigger volume of head space will help. Theres optimum and then there’s good enough.
I think either way gets the job done. Though not exactly his method, thanks to Mark the majority of my starters going back to January have been 1L in a flask, hit with the O2 wand and not stirred. I usually get HK in around 7-8 hours this way. It’s easy to miss. My results seem to match those reporting on the 1G jug “shake like it owes you” method.
Edit: Thanks you too, Jim. I seem to remember you talking about hitting your starters with the wand and stirring slowly around that time.
Good info, thanks.
I used a 5 L Erlenmeyer with a solid stopper and was able to shake well. The short krausen time fooled me. I totally expected at least 12 hours. Now I can work it into my timeline.
Yes I give 1200ml (because that’s about what I can pour off of a 1/2 gallon canned wort before I get to the trub) with o2 for guesstimate 20-30 seconds. I give it a few shakes then add the yeast. I cover with foil and leave it alone. At about 8 hrs its ready.
What was the strain? How big was the Erlenmeyer? I need data points.
I have always said that my method was a poor man’s O2 bottle and diffusion stone. Your results matching mine leads me to believe that having the wort saturated early may make a difference in the length of the lag phase.
I wish that I was closer to retirement. I would have more time to run experiments that I need to run. I barely have enough time to brew and maintain my yeast bank. I finally managed to subculture two strains today that I have put off subculturing since April. The slants that held the strains were subcultured over a year ago, and one of the cultures is pain in the backside to grow on solid media. I inoculated 40ml of autoclaved wort with one of the strains even though I do not plan to use it for a couple of weeks because I did not want to have to subculture the strain in a few weeks. That choice is going to cause me to perform an intermediate step.
just for reference, my stirred starters dont smell or taste bad nor laden with anything foul…not sure why just is the case.
I agree. I don’t understand why people say they are having stirred starters taste/smell bad/foul. Mine pretty much always smell like beer and usually a fairly clean version of the batch I plan on making since it just has extra light DME in it. If it smells off, then I don’t use it (dry yeast to the rescue), but I have only had that happen once in my 10+ years of brewing.
Mine for sure smell stale. Think back to college when you had to clean up the fallen soldiers.
If your culture does not smell off, then you are not spinning it fast enough to cause much in the way of turbulence, which means that you are depending on the tiny amount of surface area in the flask for O2 pickup.
Like said, not sure as reasons why. I use pure o2 before pitching and turning stir plate on.my flask is 4L.
Therein lies the difference between the way that you make a stirred starter versus 99.9% of the home brewers that use a stir plate. You would achieve equal or better results without stirring.
Will be doing exactly that for this weekends IPA with wlp090. Using a vial with 1 liter 1.040 wort, using O2 and then just let it reach high krausen and pitch into my IPA. looking forward to trying it out.
I’d guess though that the increased O2 pickup with a stirred starter is to do with increasing the concentration gradient much more than it does with increasing surface area. I’d also guess that a gentle stir would be enough to get you most of the way there. Movement in a solid beer fermentation seems nearly on par with what I get with stir plates with a gentle dimple.
And by my calcs there is way more O2 in the headspace of a starter than is needed to re-saturate the wort many, many times over. The only reason I use foil is because it keeps the neck sanitary/clean.
You are not getting anywhere near the level of O2 pickup that would you obtain in a shaken, not stirred culture or direct O2 injected culture of equal size if you are only gently stirring the culture. Not to mention that it is taking much longer to pick up O2 than in a shaken, not stirred starter or a directly injected starter. I have already shown that surface area to volume ratio trumps laminar or turbulent flow.
I don’t recall that being demonstrated, either experimentally or theoretically. I’m no yeast expert but I have done a lot of diffusion research. And I’m not talking about initially saturating the wort, but maintaining saturation as the yeast consumes the O2.
If you scroll down to Example 18-1.1 Aeration of a fermentation broth, you will discover that my assertion that increasing the surface area per unit volume trumps increasing the mass transfer coefficient (i.e. increasing laminar or turbulent flow) is correct. Gas-liquid foam, with its high specific surface area, is one of the reasons, if not the sole reason why the Shaken, not stirred works as well as it does for being such a trivial technique.
The average culture that is shipped with 100B cells contains at least 50B cells when pitched. That’s at most two replication periods when pitched into 1L of wort. Brewing yeast cells are Crabtree positive, which means that they do not respire in wort. How much O2 does a culture need post lag phase? Additionally, having fully saturated wort from the time zero reduces the lag period, which allows the exponential phase to start earlier.
Finally, there is no compelling evidence that supports the notion that a covered, gently stirred culture is continuously aerated. What I found interesting is that Neva Parker stated that a stir plate does not aerate culture when asked last week. Here is a scientist who runs the analytical side of White Labs claiming that a stir plate does not aerate a culture. If anyone has the equipment to test such an assertion, it is Neva.