Hello I am going to do a 4L starter now my question is how long would one leave on the stir-plate . I know for 2L yeast starter’s I let them go for 18hours on stirplate an then let it set for another 18hours off stirplate for a total of 36hrs in total before I cold crash them. But I never made a 4L starter before an I just wondering how long to leave it on stir-plate. The reason I doing a 4L starter is I am brewing a maibock beer.
Plan for the same amount of time but allow extra time before your brew day just in case. It will take longer if you plan a certain amount of time and schedule the brew day according to that plan. I’ll often make large starters a week ahead of time. This allows time for refrigeration to drop all the yeast out of suspension to get the starter ready for decanting and pitching.
Me do start creating my starters like 5 days before brewing day. So the yeast in the fridge can settle. Take it out 4 hours before i start brewing. So it can warm up. To room temp
What yeast are you using and what volume of beer are you making?
I’d probably do a 2L starter then step up to 4L. One way yeast survive is to crowd out any bacteria that may be attempting to grow in the wort. But if the yeast cells are initially spread too thin, the bacteria may have gained a foot-hold before the yeast can reach that dominant stage. For each step, I think your stir plate times are good.
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My poor stir plate is collecting dust in the closet. I’ve gone all in on shaken not stirred yeast starters(SNSYS), and bump it up a bit for bigger beers, but not much…now if I made some 1.100 OG monster I might break out the stir plate for that.
It’s just easier and you get a good aerobic workout shaking that thing.
I looked in my notes and found this url: Just say "no" to yeast rinsing
It is about yeast rinsing but first two paragraphs are what I remembered:
A yeast culture “owns” a batch of wort by shutting out competitors. It rapidly consumes dissolved oxygen, which shuts out aerobic microorganisms. A yeast culture also lowers the pH of the medium from around 5.2 to around 4.2, which shuts out pH sensitive anaerobic microflora. The final defense that a yeast culture mounts is the production of ethanol, which is toxic to microorganisms, including the culture itself.
…
Bacteria cells multiply three times faster than yeast cells (i.e, an eight-fold increase in bacteria cell count for every two-fold increase in the yeast cell count), which means that a small infection can overtake a larger yeast culture when pitched into fresh wort.
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All true. Pitching enough healthy yeast for the wort gravity and type(ale vs Lager) is of paramount importance. Definitely a source of anxiety when a fermentation doesn’t take off as expected. Giving bacteria any foothold could be a disaster.
Whenever it reaches high krausen, its ready. I’ve only made 2L starters though and that only takes 18 hours or so depending on the ambient temperature of the room. Typically will make that at 8pm and brew the next day. Then pitch around 2 or 3 PM since I dont bother cold crashing them. I might with a 4 Liter starter though…
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Several years ago I gave up stir plates and pitch calculators and started using the “Shaken Not Stirred” method. It works at least as well as what I was doing before, and is faster and easier. Old Dog...New Tricks | Experimental Homebrewing
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