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Repitching rates for newly harvested yeast slurry...


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#21 Lagerdemain

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Posted 27 March 2009 - 11:36 AM

I will say just one thing. I have found that it is not necessarily a given that the most vigorous, fastest fermentations result in the best beer. I think a lot of people pitch more yeast than they otherwise might, expecting that because they get a more violent, faster fermentation that it will necessarily improve the beer. My own experience has been rather the opposite, particularly for lagers. One must consider that the more active the primary fermentation, the more metabolic activity going oin at any particular time by the yeast, and the more the temperature of the fermenting wort will rise.I've found I enjoy my beers far more if I underpitch with respect to the well-known pitch rate calculators than otherwise - that is, of course, assuming extremely careful attention to sanitation and temperature control. Something to consider, anyway - take from it what you will, but in this hobby, my experience is that there's absolutely no unrestricted panacea or free lunch.

#22 Big Nake

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Posted 27 March 2009 - 12:28 PM

Thanks Lager. I also think there is confusion when your hear someone say, You need a HUGE starter for a lager! or whatever. Who says what HUGE is? I'm strictly talking about harvested slurry and I think I may have gone a little crazy in the past. I am going to harvest the same way, maybe do the washing thing and pitch a little less than I ordinarily would. There have been times when I save yeast in 12oz bottles, put a #2 stopper & airlock on there and save it. But there is usually at least twice or 3 times that amount in my primary which means that if I save that yeast in a large flask and put it into the fridge so I can pitch it into a new batch the same day... and I'm pitching ALL of it... I'm pitching somewhere between 24 and 36 ounces of harvested slurry. What does that convert to in mls? Seems like too much to me. Cheers.

#23 Lagerdemain

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Posted 27 March 2009 - 01:19 PM

Thanks Lager. I also think there is confusion when your hear someone say, You need a HUGE starter for a lager! or whatever. Who says what HUGE is? I'm strictly talking about harvested slurry and I think I may have gone a little crazy in the past. I am going to harvest the same way, maybe do the washing thing and pitch a little less than I ordinarily would. There have been times when I save yeast in 12oz bottles, put a #2 stopper & airlock on there and save it. But there is usually at least twice or 3 times that amount in my primary which means that if I save that yeast in a large flask and put it into the fridge so I can pitch it into a new batch the same day... and I'm pitching ALL of it... I'm pitching somewhere between 24 and 36 ounces of harvested slurry. What does that convert to in mls? Seems like too much to me. Cheers.

Ken, I'm too lazy to look it up! But I'll tell you that I don't come anywhere close to pitching the amount of yeast that I hear others pitching. I think that, perhaps, I'm more patient and willing to wait for activity than a lot of other brewers. I also don't repitch yeast - I grow up new starters from the dregs of previous starters. I'm quite profligate in my use of canned starter wort to generate new starters.

#24 chuck_d

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Posted 27 March 2009 - 01:26 PM

I'm pitching somewhere between 24 and 36 ounces of harvested slurry. What does that convert to in mls?

24 fl oz = 709.764 mL36 fl oz = 1064.646 mL(I just typed this into the converstion calculator in my spreadsheet, linked in my sig)

#25 Big Nake

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Posted 28 March 2009 - 09:21 AM

24 fl oz = 709.764 mL36 fl oz = 1064.646 mL(I just typed this into the converstion calculator in my spreadsheet, linked in my sig)

Thanks Chuck... definitely too much yeast according to the yeast calculator on mrmalty.com, no question. I just need to scale it back a little.

#26 zymot

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Posted 28 March 2009 - 10:44 AM

Pitching Rate and Overpitching. A topic close to my speculative and empirical knowledge heart.In the past on other boards, I have openly questioned the monster some home brewers make, e.g. "I make a 5 liter starter." Making a starter 1/4 the size of your batch! Yikes. The mrmalty.com pitch rate calculator is often sited as why you need to make as big of a starter as possible.This goes against what I see and know others have done.Direct pitching a White Labs vial or Wyeast smackpack. People make beers just fine by doing this.It is conventional wisdom that you do not need to make a starter for dry yeast.IIRC, a packet of dry yeast has about 2.5x the cell count of a reasonably fresh vial or smackpack. (So a starter only needs to get to dry yeast [250 billion] quantities)In his recipe book, Jamil typically specifies (for average strength ales) "make an appropriate starter" or pitch 2-2.5 vials of liquid yeast. (What do you do with 1/2 tube of yeast?)Jamil also warns that over pitching by as little as 20% can negatively affect you beer.I know of side by side tests. 10 gallons split. 5 gallons got a White Labs tube, 5 gallons got a starter, same strain. No difference in the two beers was perceived.I recently made some beers re-using Wyeast special strains. I did some pitching of good volume of slurry. The second generation beers were too clean and low in the ale flavors I like.Recently (source White Labs - I think) there has been discussion that the yeast that comes in a White Labs vial or a Wyeast smackpack is different in nature than yeast grown in a starter or harvested from a previous batch. The 100 billion cells from these sources is not equal to 100 billion of harvested yeast. So these sources of yeast are truly "Direct Pitchable"Granted I am working with anecdotal data. But taken as an aggregate of information, my gut tells me that pitching rates might be often exaggerated and/or the negative affects of "under pitching" might be exaggerated and/or overpitching might be easier to do.Everybody has their own comfort level. I tend to agree with the OP. Me, I am going to continue to make 1 or 2 liter starters. I will probably back off on volume of re-used yeast. It is what I makes sense to me.zymot

#27 chuck_d

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Posted 28 March 2009 - 11:05 AM

Pitching Rate and Overpitching. A topic close to my speculative and empirical knowledge heart.In the past on other boards, I have openly questioned the monster some home brewers make, e.g. "I make a 5 liter starter." Making a starter 1/4 the size of your batch! Yikes. The mrmalty.com pitch rate calculator is often sited as why you need to make as big of a starter as possible.This goes against what I see and know others have done.Direct pitching a White Labs vial or Wyeast smackpack. People make beers just fine by doing this.zymot

I make 3+ liter stirplate starters for 10 gallons of lager. For my house lager at an OG of 1.055 (13.6) with 10.25 gallons in the fermenter my spreadsheet tell me to make just over 3 liters of starter if I'm using a stirplate (but to get the same cell count I'd have to make a 13! liter starter if it was just a jug I didn't aerate). I based my math on the article by MB Raines on the Maltose Falcons site: https://www.maltosef...t_Culturing.php If you trust that reference using a stirplate allows you to get drastically higher cell counts for the same volume of starter. I have made good beers by just pitching a vial, but one thing that even small none aerated starters do for you is get the vitality of an old vial up prior to pitching, even though you'll likely still be underpitching. I couldn't reverse engineer the mr. malty calculator, and used to use a table based on the one in the appendix of Jamil's book, but since finding MB Raines's page there is no need to reverse engineer it and I just calculate my starters based on that data.

Edited by chuck_d, 28 March 2009 - 11:05 AM.


#28 japh

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Posted 28 March 2009 - 02:55 PM

24 fl oz = 709.764 mL36 fl oz = 1064.646 mL(I just typed this into the converstion calculator in my spreadsheet, linked in my sig)

Also, Google does conversions for you if you ever need it (type 24 fl oz in ml and it'll give it to you. Firefox will do it in the google search box in the right hand corner).

#29 onthekeg

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Posted 28 March 2009 - 03:11 PM

If you dump the cake into a large glass jar, (1 gallon is the largest I have), I add boiled and cooled water to about 80% capacity of the jar. I will swirl it, set the timer for about 20 minutes. I will come back and use a siphon and try to get the light cream colored product that will settle out on top of the rest of the stuff. I will hold the tube right above it, create a siphon, and watch it suck the yeast out. This works well, it may be a little nerdy but I get plenty yeast that is clean and virulent from this technique.


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