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Stir Plate

Quick question: When using a stir plate, I’ve always let the plate spin right up until I’m ready to pitch into my wort. Would I be better off letting the starter sit un-agitated for a bit and let the yeast settle to the bottom? I assume I would then decant the top portion and pitch only the slurry left behind. Just curious what the pros and cons of each technique would be. Any help is appreciated!!

When the starter wort is decanted, you won’t be pitching as much nasty tasty oxidized wort.

Yeah. I like to cold crash (well, actually cool them to pitching temp) my starters for 24 hr and decant off most of the liquid.

I always chill and decant my starters nowadays. If you’ve ever tasted the wort from a starter, you will realize that it will not improve the quality of your beer, even if it is a relatively small amount compared to the batch size…

I cold crash and decant ALL starters.

Same here.

I let mine spin right up until the time I pitch. I make a 1600 ml starter, decanting 500 ml into a sterilized Mason jar to save it for a future brew and the rest into my chilled wort. 1100 ml in a 5.5 gallon batch is the proverbial drop in the bucket. Unless you’ve made your starter with chlorinated water there is nothing in starter wort that will break the flavor threshold at that dilution rate.

I disagree. I frequently make starters larger than 2L which is just over 1/2 a gallon. A dilution of 10:1 would still be detectible. It wouldn’t ruin the beer but I also strive to make the absolute best beer possible. It’s a step that requires some planning but worth it in my opinion.

So you don’t think any significant amounts fermentation byproducts created in the starter wouldn’t be cleaned up by the yeast once the main batch is finished actively fermenting? With such a healthy pitch rate I fail to see how that isn’t a possibility.

It’s not so much fermentation byproducts, its creating a “beer” with no hops at very high temps and oxidizing the crap out of it. That “beer” tastes terrible :slight_smile: try it sometime and I bet you won’t pour it in your beer ever again.

You’re also pouring a significant amount of active, healthy yeast down the drain. This from Chris White and Jamil Zainasheff:

https://www.homebrewersassociation.org/forum/index.php?topic=15110.5;wap2

Drinking a mouthful of corn syrup tastes pretty overpowering too. Dilute it 10:1 in a glass of Coca Cola in I bet you won’t be able to taste the difference…

This is the purpose of putting in the fridge for 2 days and cold crashing it. All yeast should drop out of suspension to the bottom and you only decant off the nasty stuff on top. I haven’t had attenuation issues or off flavors from stessed yeast doing it this way so no matter what CW and JZ say, I am confident I’m pitching enough healthy yeast into my brew.

Also keep in mind that the “Yeast” book was written from the perspective of professional brewers and a lot of their calculations were extrapolated from REALLY large samples and scaled down linearly which isn’t always accurate.

I disagree. I frequently make starters larger than 2L which is just over 1/2 a gallon. A dilution of 10:1 would still be detectible. It wouldn’t ruin the beer but I also strive to make the absolute best beer possible. It’s a step that requires some planning but worth it in my opinion.[/quote]

I agree with you, Matt. My starters are always in the 2-3 qt. range and I’ve found (unfortunately) that amount does have a negative impact on flavor.

The starter wort is already oxidized. The yeast isn’t gonna clean that up.

Aren’t you confusing aeration with oxidation? The oxidation that creates off-flavors occurs in finished beer that has been packaged, especially if the finished beer contains no active yeast. A starter wort is an environment with a massive amount of active yeast (which is, of course, the whole point of making a starter!) which will consume any and all oxygen over time.

[quote]Yeast, during its early growth stages in a nutrient-rich wort, is an air scavenger that will use up all of the air that is available in the solution. It not only loves air at this stage, it needs it. So it’s okay to introduce air at the yeast-pitching stage because we know that a) the yeast needs it, and b) the yeast will remove all of it from the wort during the yeast’s growth process.

The oxidation reaction occurs in finished beer most often during racking after pri­mary fermentation and during bottle filling. These are the times to be most careful in avoiding unnecessary splashing of the beer. Oxygen, if introduced at this stage, will chemically react with beer flavor compounds, causing the beer to grow stale. Heat and warm storage of the finished beer will accelerate the oxidation process.[/quote]

You might also be confusing correlation with causation. Perhaps you had a batch where you pitched the entire starter into a fresh batch of wort, only to end up with bad tasting beer. You can certainly correlate the action with the result (I did A and B was the result, so I’m never doing A again), but can you definitively conclude that A caused B? Is there experimental evidence controlling for other possible variables (and in brewing there are many!), and is this experiment repeatable by independent, confirmatory studies?

Finally, please don’t take any of this as me being argumentative. I relish the vigorous, respectful debate that happens on homebrewing message boards and want to add to that debate. It truly is a community. I also have observed that there are a lot of “rules” based on anecdotal experience. It’s harder to find actual science to back these rules up. Maybe that’s why so many people add the YMMV disclaimer.

[quote=“Ken in MN”]Aren’t you confusing aeration with oxidation? The oxidation that creates off-flavors occurs in finished beer that has been packaged, especially if the finished beer contains no active yeast. A starter wort is an environment with a massive amount of active yeast (which is, of course, the whole point of making a starter!) which will consume any and all oxygen over time.

[quote]Yeast, during its early growth stages in a nutrient-rich wort, is an air scavenger that will use up all of the air that is available in the solution. It not only loves air at this stage, it needs it. So it’s okay to introduce air at the yeast-pitching stage because we know that a) the yeast needs it, and b) the yeast will remove all of it from the wort during the yeast’s growth process.

The oxidation reaction occurs in finished beer most often during racking after pri­mary fermentation and during bottle filling. These are the times to be most careful in avoiding unnecessary splashing of the beer. Oxygen, if introduced at this stage, will chemically react with beer flavor compounds, causing the beer to grow stale. Heat and warm storage of the finished beer will accelerate the oxidation process.[/quote]

You might also be confusing correlation with causation. Perhaps you had a batch where you pitched the entire starter into a fresh batch of wort, only to end up with bad tasting beer. You can certainly correlate the action with the result (I did A and B was the result, so I’m never doing A again), but can you definitively conclude that A caused B? Is there experimental evidence controlling for other possible variables (and in brewing there are many!), and is this experiment repeatable by independent, confirmatory studies?

Finally, please don’t take any of this as me being argumentative. I relish the vigorous, respectful debate that happens on homebrewing message boards and want to add to that debate. It truly is a community. I also have observed that there are a lot of “rules” based on anecdotal experience. It’s harder to find actual science to back these rules up. Maybe that’s why so many people add the YMMV disclaimer.[/quote]

I think what he was saying is that if the starter is on the stir plate AFTER it’s early growth stage (like more that 6-12hours for a starter), then the yeast will no longer consume the oxygen and the starter will now be oxidized. The flavor of oxidized beer will be dumped into your fresh beer, will not then be consumed. Yes they will consume the oxygen but not the flavor of oxidized starter wort. I do it both ways and can’t tell the difference but ymmv.

I’m just speculating but I don’t think that the yeast can consume as much oxygen as starter on a stir plate can provide. Just like if you were bottle conditioning you wouldn’t want to splash around your beer because the yeast are gonna eat the oxygen and it wont oxidize the beer. Yes they will eat some but not all.

[quote=“Ken in MN”]Aren’t you confusing aeration with oxidation? The oxidation that creates off-flavors occurs in finished beer that has been packaged, especially if the finished beer contains no active yeast. A starter wort is an environment with a massive amount of active yeast (which is, of course, the whole point of making a starter!) which will consume any and all oxygen over time.

[quote]Yeast, during its early growth stages in a nutrient-rich wort, is an air scavenger that will use up all of the air that is available in the solution. It not only loves air at this stage, it needs it. So it’s okay to introduce air at the yeast-pitching stage because we know that a) the yeast needs it, and b) the yeast will remove all of it from the wort during the yeast’s growth process.

The oxidation reaction occurs in finished beer most often during racking after pri­mary fermentation and during bottle filling. These are the times to be most careful in avoiding unnecessary splashing of the beer. Oxygen, if introduced at this stage, will chemically react with beer flavor compounds, causing the beer to grow stale. Heat and warm storage of the finished beer will accelerate the oxidation process.[/quote]

You might also be confusing correlation with causation. Perhaps you had a batch where you pitched the entire starter into a fresh batch of wort, only to end up with bad tasting beer. You can certainly correlate the action with the result (I did A and B was the result, so I’m never doing A again), but can you definitively conclude that A caused B? Is there experimental evidence controlling for other possible variables (and in brewing there are many!), and is this experiment repeatable by independent, confirmatory studies?

Finally, please don’t take any of this as me being argumentative. I relish the vigorous, respectful debate that happens on homebrewing message boards and want to add to that debate. It truly is a community. I also have observed that there are a lot of “rules” based on anecdotal experience. It’s harder to find actual science to back these rules up. Maybe that’s why so many people add the YMMV disclaimer.[/quote]

I totally understand. I am not a scientist and still consider myself a novice when it comes to homebrewing. I can only speak from what limited knowledge I have on the subject from books and from experience. If you are pitching your yeast at high krausen so it’s true you probably won’t have oxidized your starter. I run my starters for 48 hours. I can’t exactly plan to make a starter and pitch at high krausen because my brew days can be delayed anywhere from a couple hours to 2 days depending on life. My understanding is that oxygen is only needed during the growth phase of the fermentation so any oxygen added after that will be detrimental to the flavor of the beer.

Mostly my choice to cool and decant is just a matter of philosophy. Have you ever sipped on the starter “beer”? It tastes terrible! Just the thought of adding it to my beer bothers me. You may be right, it may be completely undetectable. But I’d rather not take the risk. Willingly pouring nasty tasting liquid into something that takes many hours of work and many weeks/months of time to develop and mature, goes against my philosophy of trying to make the best brew possible.

[quote=“Ken in MN”]Aren’t you confusing aeration with oxidation? The oxidation that creates off-flavors occurs in finished beer that has been packaged, especially if the finished beer contains no active yeast. A starter wort is an environment with a massive amount of active yeast (which is, of course, the whole point of making a starter!) which will consume any and all oxygen over time.

[quote]Yeast, during its early growth stages in a nutrient-rich wort, is an air scavenger that will use up all of the air that is available in the solution. It not only loves air at this stage, it needs it. So it’s okay to introduce air at the yeast-pitching stage because we know that a) the yeast needs it, and b) the yeast will remove all of it from the wort during the yeast’s growth process.

The oxidation reaction occurs in finished beer most often during racking after pri­mary fermentation and during bottle filling. These are the times to be most careful in avoiding unnecessary splashing of the beer. Oxygen, if introduced at this stage, will chemically react with beer flavor compounds, causing the beer to grow stale. Heat and warm storage of the finished beer will accelerate the oxidation process.[/quote]

I’m with ya…I don’t take it as being argumentative at all. All I can tell you is that I have tasted starter wort and despite the theory that the yeast will consume the O2, it tastes badly oxidized. Many years ago I split a batch and pitched an undecanted starter into one half and a decanted starter into the other. I could taste the difference, although I did not do a blind triangle. Decanting is easy and offers no downside, so I’d rather not take the chance.

You might also be confusing correlation with causation. Perhaps you had a batch where you pitched the entire starter into a fresh batch of wort, only to end up with bad tasting beer. You can certainly correlate the action with the result (I did A and B was the result, so I’m never doing A again), but can you definitively conclude that A caused B? Is there experimental evidence controlling for other possible variables (and in brewing there are many!), and is this experiment repeatable by independent, confirmatory studies?

Finally, please don’t take any of this as me being argumentative. I relish the vigorous, respectful debate that happens on homebrewing message boards and want to add to that debate. It truly is a community. I also have observed that there are a lot of “rules” based on anecdotal experience. It’s harder to find actual science to back these rules up. Maybe that’s why so many people add the YMMV disclaimer.[/quote]

[quote=“gdtechvw”]I think what he was saying is that if the starter is on the stir plate AFTER it’s early growth stage (like more that 6-12hours for a starter), then the yeast will no longer consume the oxygen and the starter will now be oxidized. The flavor of oxidized beer will be dumped into your fresh beer, will not then be consumed. Yes they will consume the oxygen but not the flavor of oxidized starter wort. I do it both ways and can’t tell the difference but ymmv.

I’m just speculating but I don’t think that the yeast can consume as much oxygen as starter on a stir plate can provide. Just like if you were bottle conditioning you wouldn’t want to splash around your beer because the yeast are gonna eat the oxygen and it wont oxidize the beer. Yes they will eat some but not all.[/quote]

That’s it exactly. I have never done a starter in 6-12 hours. I make 2-3 qt. starters and give then at least 36 hours on the stir plate.

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