I know the math is simple when converting a 5 gallon receipe to a 2.5 gallon batch (just divide grains & hops by 2). However, do I cut the yeast in half or just put the same amount in as I would use for a 5 gallon batch?
Question regarding yeast on small batches
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Short Answer: Yes, but keep in mind that different worts have different pitching rates. Always use a calculator like yeastcalc.com.
Long Answer: If you're using a packet of dry yeast with a medium gravity (1.060 or less) wort, then you can pitch half a packet with good results. If you're using liquid yeast, you may be able to get away with just pitching the vial instead of making a starter. But always use a calculator like yeastcalc.com.
Long Answer: If you're using a packet of dry yeast with a medium gravity (1.060 or less) wort, then you can pitch half a packet with good results. If you're using liquid yeast, you may be able to get away with just pitching the vial instead of making a starter. But always use a calculator like yeastcalc.com.
tallmike
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Please, experienced brewers correct me if I'm wrong, but the yeast you pitch is just a starter for the yeast that grows in the wort.
Pitching double yeast shouldn't hurt a thing. It's like lighting a fireplace in two places instead of one, either way the fuel (sugar) is what burns (ferments), and it all gets burned either way...
Pitching double yeast shouldn't hurt a thing. It's like lighting a fireplace in two places instead of one, either way the fuel (sugar) is what burns (ferments), and it all gets burned either way...
Not really
If you under or severely over pitch you are hindering the ability of the yeast to properly ferment the beer by stressing them out. Stressed yeast can produce off flavors or not fully attenuate.
If you under pitch you are making the yeast work harder to multiply up to a cell count to properly ferment and if you severely over pitch the yeast may not reproduce enough to function properly and quit before the job is done.
Over pitching is more difficult to do on a home brew scale but under pitching is a very common problem.
This is a very simple explanation to say the least
freisste
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Depends. You don't want yeast multiplying a lot of times in your beer, because you can get off flavors. That's why you want to pitch at an appropriate rate (I think it is something like 750k per milliliter per degree Plato for an ale). If you severely under pitch (start a large fire with a single match), it takes much longer to burn all the fuel. Yes, the fuel all burns (in the fire case, sometimes not in the yeast case). Also, the larger the yeast colony, the less likely another colony of something else can take over the batch.tallmike said:
Also, a big over pitch can cause off flavors. But I think they are less severe than under pitching. For instance, pitching 25% too much yeast will have less noticeable off flavors than 25% too little.
Just use yeastcalc.com. Or mrmalty.com. Or one of several others. Or set up a spreadsheet with the math I mentioned above. Yeastcalc.com doesn't have magical capabilities, it's pretty simple math. But it is way easier to use than to make your own.
TexanRudeboy
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tallmike said:
It is generally believed that pitching rates effect ester production. During the reproduction phase they produce enzymes that are believed to play a major role in esterification of fatty acids. Of course other inputs (temp, ph, and nutrient levels etc) stress the yeast in various ways effecting ester production also though.
chickens4life
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a second problem that can be caused by overpitching is a lack of flavor development, a lot of the flavor compounds released by yeast are byproducts of growth and stress. I have a couple of times pitched an entire yeast cake before from a 5 gallon batch to another 5 gallon batch. and while the ferment was very healthy, it only lasted 24-36 hours and was done (that is for a 1.070 ale). But over pitching is not a common home brewing problem, most people struggle to get enough yeast.
So in specifics: I'm brewing a 5.25 gal batch that I plan on splitting so I can compare the differences of Nottingham dry and WL001. Yeastcalc.com recommends 100 billion cells for 1.069 @ 2.6 gallons. My yeast vitality is 67 billion cells. Even at a 0.8 liter starter, which may be the smallest I have glassware for, I get 165 billion cells, 65% too much. Any issues there or is there a fix? Just brainstorming, but could I just eyeball out a little less yeast from the vial? Seems like too much guesswork. Could I just skip the stir plate and do an intermittent shake? That would reduce cell production some.
It's a 2l flask it gets really wide and shallow below .8 and not really a good geometry for fermenting I was thinking. I'm probably just over thinking it. It's running now and looks good.
This is exactly the issue I'm grappling with nowadays. I brew 2.5 gallon batches and had been doing a yeast starter on a stir plate without considering that I might be grossly over pitching.
So I attempted a fix for my last brew: I needed 105 billion yeast cells, but my viability was only 59 billion. My starter calculated to produce something like 185 billion cells so what I did was I calculated the difference and then determined how many mL of starter wort I would need to pour off to hit my target. I ran it on the stir plate for 21 hours and then immediately decanted what I needed to (I believe it was something like 480 mL - I poured into a measuring cup) and then cold crashed it for a few days. I also erred on the side of slightly over pitching, shooting for 115 billion cells, just in case my efficiency came in higher than expected.
My fermentation was great. 5 hour lag time, 3.5 days until the krausen totally fell. I haven't taken a gravity yet, but I'll report back when I do. I hope this method makes sense and actually works out.
Sent from my SCH-I545 using Home Brew mobile app
So I attempted a fix for my last brew: I needed 105 billion yeast cells, but my viability was only 59 billion. My starter calculated to produce something like 185 billion cells so what I did was I calculated the difference and then determined how many mL of starter wort I would need to pour off to hit my target. I ran it on the stir plate for 21 hours and then immediately decanted what I needed to (I believe it was something like 480 mL - I poured into a measuring cup) and then cold crashed it for a few days. I also erred on the side of slightly over pitching, shooting for 115 billion cells, just in case my efficiency came in higher than expected.
My fermentation was great. 5 hour lag time, 3.5 days until the krausen totally fell. I haven't taken a gravity yet, but I'll report back when I do. I hope this method makes sense and actually works out.
Sent from my SCH-I545 using Home Brew mobile app
Dry yeast on small batches, I toss in the whole thing like I would a 5 gallon batch. So far no side effects and I don't like keeping up with an open packet of dry yeast laying around. It tends to disappear or get spilled somehow so I just toss it all in there and let r rip.
I WILL do a normal starter and split it 50/50 for smaller batches on liquid yeast however...I usually plan on making 2 smaller brews that use the same yeast and then do a normal 5 gallon starter(using yeastcalc for pitch rates) on the stir plate, slurry it up, half it in 2 sanitized mason jars and pitch one, refrigerate the other until the second batch is ready.
Works well.
:fro:
I WILL do a normal starter and split it 50/50 for smaller batches on liquid yeast however...I usually plan on making 2 smaller brews that use the same yeast and then do a normal 5 gallon starter(using yeastcalc for pitch rates) on the stir plate, slurry it up, half it in 2 sanitized mason jars and pitch one, refrigerate the other until the second batch is ready.
Works well.
:fro:
