Pitching rates vs cell growth?

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Kev888
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Re: Pitching rates vs cell growth?

Post by Kev888 » Fri Oct 14, 2011 10:57 am

I have the same issue, and was similarly unprepared for it :-) I now have a 5L borosilicate beaker, which whilst still costly is notably cheaper than the conical flasks I could find at the time. Annoyingly it doesn't 'quite' fit in my microwave so I very nervously have to put it on my hot-plate, but it'll be fine when I get a gas hobb next year.

But some pitching rates really suggest bigger starters than that can take. I've not tried it yet, but I've just bought a cheapo but large non-stick-coated aluminium stock pot from ebay - on the basis that (unlike most stainless pots I can find) it isn't at all magnetic, and so will hopefuly interfere less with the stir bar, alkthough I daresay it'll still cause induction currents. Its profile is a bit more squat than I would like (and it doesn't really fit my hobb either); taller and narrower would be better, but I seem to be able to get a vortex in water using the stirbar so hopefully it will work out.

Or I just use four packs of US-05... :twisted:

Cheers
Kev
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greenxpaddy

Re: Pitching rates vs cell growth?

Post by greenxpaddy » Fri Oct 14, 2011 8:08 pm

Thats a good shout Kev I've bought one of those beakers.

Should be a doddle now :lol:

greenxpaddy

Re: Pitching rates vs cell growth?

Post by greenxpaddy » Wed Oct 19, 2011 7:03 pm

That huge beaker arrived, looks like it will fit easily onto the stirplate.

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Kev888
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Re: Pitching rates vs cell growth?

Post by Kev888 » Wed Oct 19, 2011 8:06 pm

Good stuff! Yes they're quite big - you can see why I'm nervous of it on my hotplate.. 'so far' its been alright (unlike my asda measuring jug) but I'd be a lot happier with gas. Maybe I'll start using my camping stove or something...

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Kev
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greenxpaddy

Re: Pitching rates vs cell growth?

Post by greenxpaddy » Wed Oct 19, 2011 9:34 pm

What about a wire gauze

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Kev888
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Re: Pitching rates vs cell growth?

Post by Kev888 » Wed Oct 19, 2011 9:45 pm

yes possibly - though I think even with that gas would still be safer. My exploding measuring jug may have made me over-nervous though, the beaker has been fine so far..

Cheers
Kev
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greenxpaddy

Re: Pitching rates vs cell growth?

Post by greenxpaddy » Mon Nov 21, 2011 12:30 pm

Boiled up 4l of DME in the beaker with a wire gauze under. Did it slowly, took a good hour. Fits beautifully onto the stirplate base and has been whirring away joyfully since, super vortex. Chuffed :) :)

greenxpaddy

Re: Pitching rates vs cell growth?

Post by greenxpaddy » Wed Mar 07, 2012 8:35 am

Quite amazed at the pitching recommendations from Wyeast versus Mr Malty

For my latest ale Mr Malty recommended a pitch of 890bn cells but Wyeast recommended 660bn cells

Clearly both will brew a beer but they will be vastly different in flavour. Goes to show you shouldn;t get so hung up on exact pitching rates unless you really want to recreate the same beer or brew to a particular style.

Incidentally, most brew recipes NEVER talk about pitching rate and fermentation temperatures which is probably the main variable in flavours that characterises a beer

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Re: Pitching rates vs cell growth?

Post by Kev888 » Wed Mar 07, 2012 11:43 am

I don't think its 'that' critical for many home brewers, as long as you have enough, and unless you count the cells its all a rough estimate in any case. Perhaps the calculators are making different assumptions too (on yeast health and ageing characteristics and so on) - it sometimes seems that nothing in brewing is ever really agreed upon!

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Dennis King
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Re: Pitching rates vs cell growth?

Post by Dennis King » Mon May 07, 2012 6:02 pm

Like Kev I am reading the yeast book and I'm now worried that I'm under pitching. I have for a long while used 1 vial of Whitelabs and made up a 1lt starter with 100gms of sprymalt. When fermented out I remove the old wort and increased the starter to 2 lts with 200gms of spraymalt. When fermented it's then split 6 ways. When I go to use each one I make a fresh 1lt starter which when added to my brew is normally fermenting within a few hours. Trying to get my head around the pitching rates in the book but from what I've read they don't seem to allow for splitting yeast. As I am always looking to improve or fine tune my beers I am now wondering would I be better starting out with a bigger starter or stepping up to a bigger started before splitting or maybe a bigger starter after splitting.

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Re: Pitching rates vs cell growth?

Post by gregorach » Mon May 07, 2012 6:18 pm

Well, you probably don't get very much growth on the 1L -> 2L step... You don't say whether you're using a stir plate. If not, I'd certainly say you should consider going to a 2L starter from each split. If you're storing your splits for more than a couple of months, I'd also consider revitalising them (the procedure's in the book) before making the starter.
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Re: Pitching rates vs cell growth?

Post by Dennis King » Mon May 07, 2012 6:35 pm

Thanks Dunc, I'm not using a stir plate but I agitate quite a few times. As I tend to brew every other week so the splits have been lasting 12 weeks. So if should I leave out the 1lt step and start with a 2lt one and a 2lt one when restarting. I'm still working my way through the book.

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Re: Pitching rates vs cell growth?

Post by gregorach » Tue May 08, 2012 6:09 pm

Sounds about right. Try it and see!
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Re: Pitching rates vs cell growth?

Post by Dennis King » Tue May 08, 2012 7:21 pm

Thanks again Dunc. I am having to read some of the chapters in the book more than once to take it in but will get there in the end.

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