Making Agar Slants (Slopes) - In Pictures

Share your experiences of using brewing yeast.
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Befuddler
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Re: Making Agar Slants (Slopes) - In Pictures

Post by Befuddler » Sun Aug 14, 2011 5:28 pm

Well, I've got one confirmed fail from the batch of ten slants I made.. Maybe I'll reconsider spending a tenner on a pressure cooker:

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"There are no strong beers, only weak men"

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Re: Making Agar Slants (Slopes) - In Pictures

Post by gregorach » Tue Aug 16, 2011 9:58 am

greenxpaddy wrote:There were some important lessons I learnt. The principle one was I realised how much I was underpitching. I wonder if others are doing the same without really realising it.
Hehe... I don't know how much of other people's beer you get to taste, but I find there's a very common "homebrew character", which I reckon is pretty much entirely down to underpitching. Haven't managed to figure out how to describe it though...
Overall it was clear that the wort making had become my priority. Whereas it is now clear that making good wort is not too difficult with attention to temperature. The effort should really be focussed to prepare a great yeast culture. How many really focus on that I wonder?
Sounds like you're coming round to my way of thinking. Far too many people seem to think that "brewing" just means wort production. ;)
Cheers

Dunc

greenxpaddy

Re: Making Agar Slants (Slopes) - In Pictures

Post by greenxpaddy » Thu Aug 18, 2011 9:01 pm

The multipliers are quite onerous to work out even with the book. One thing the book does not tell you in figure 5.5 is the effect of oxgenising the starter wort and shaking it.

However by manipulating the Mr Malty calculator I have worked out that Jamil reckons with a good aeration and the innoculation rate of 10million/ml you can get a multiplier of 5.5

Mr previous post yet again underestimated the yeast need for my batch! This was because they refer to a 100bn cell smack pack. This is the Activator pack. I get the Propagator pack. These start with only 25 bn cells. Holy moley

Here's todays working example for my next brew:

Wyeast 1068 ESB Produced end of May. This now has only 8bn viable cells as an estimate 34% viable

Step 1

8bn into 800ml worth gives 44bn. Inocculation rate of 10million/ml

Step 2.

Split into two conicals = 22bn in each of 2L. Innoculation rate a little over 10m/ml. Estimated multiplier of 5. Each flask (1) and (2) has 110bn.

Step 3

I need 300bn per batch So am still 80 bn short. Best way to get 80 bn is to pitch 1/4 of the yeast from one of these flasks (i.e 27bn) into 1L wort. Innoc rate of 27m/ml. Growth factor of 4. Total cells from this flask (3) = 108bn

Therefore

Flask 1 = 110bn
Flask 2 = 110bn less 1/4 = 82.5bn
Flask 3 = 108bn

Total = 300bn

If anyone has an easier way to get from 8bn to 300bn please tell me. I can't imagine how underpitched things were before!!

Wolfy

Re: Making Agar Slants (Slopes) - In Pictures

Post by Wolfy » Fri Aug 19, 2011 5:42 pm

greenxpaddy wrote:If anyone has an easier way to get from 8bn to 300bn please tell me. I can't imagine how underpitched things were before!!
Have a read through this thread: viewtopic.php?f=12&t=43405
... then pick either Dunc's or my numbers to work with and make a spreadsheet if you want/need to. :)

greenxpaddy

Re: Making Agar Slants (Slopes) - In Pictures

Post by greenxpaddy » Fri Aug 19, 2011 7:05 pm

Just posted on that thread. Thanks...

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Re: Making Agar Slants (Slopes) - In Pictures

Post by jmc » Mon Sep 19, 2011 2:16 pm

Hi
Just thought I'd add a little warning about what not to do when sanitising slant agar containers.

I got my freecycle pressure cooker at the weekend and follwing instructions on this post I added my 1st 5 30cc containers

I thought it would be a good idea to hold them together with an elastic band to stop them falling over.

Up to pressure for 30 mins to be sure.
Left to cool to below 100C then opened lid.

Result not as planned :oops:
Image
Image

Any suggestions for better containers for slants?
TIA
John

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Re: Making Agar Slants (Slopes) - In Pictures

Post by gregorach » Mon Sep 19, 2011 2:52 pm

These are what you want - autoclavable polypropylene.
Cheers

Dunc

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Re: Making Agar Slants (Slopes) - In Pictures

Post by jmc » Mon Sep 19, 2011 8:35 pm

gregorach wrote:These are what you want - autoclavable polypropylene.
Thanks gregorach. =D> I'll get some ordered

I wont chance the elastic band trick again with these. :roll:

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Re: Making Agar Slants (Slopes) - In Pictures

Post by gregorach » Mon Sep 19, 2011 8:37 pm

I would think it should be fine - polypropylene is stable to quite high temps. But I always like to have space around everything in the pressure cooker, if possible, so that it all heats evenly.
Cheers

Dunc

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Re: Making Agar Slants (Slopes) - In Pictures

Post by jmc » Mon Sep 19, 2011 11:43 pm

Wolfy wrote: .....
Polypropylene (PP) plastic can be heated and autoclaved, where other plastic such as LDPE or Polystyrene (PS) cannot....
Note to self : read the full thread before trying new stuff out #-o
Image

weiht

Re: Making Agar Slants (Slopes) - In Pictures

Post by weiht » Mon Sep 26, 2011 6:14 am

Ok, my new yeast vials are coming and I'm thinking of making slants for them as they are expensive here... Stupid question now, Agar powder is extremely easy to buy but there are so many different types, most with colouring and is sweeten. I'm guessing the agar you guys use are just plain in terms of flavour and colour, and is more of a jellying agent? Will it make a difference if im using those sweeten and coloured ones?

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Re: Making Agar Slants (Slopes) - In Pictures

Post by gregorach » Mon Sep 26, 2011 11:13 am

Not sure... I'd certainly try and avoid any colouring, so that you can see what's going on properly.
Cheers

Dunc

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Re: Making Agar Slants (Slopes) - In Pictures

Post by weiht » Tue Oct 04, 2011 8:58 am

my autoclavable tubes are not here yet, but im thinking of brewing this week... Can i use an empty whitelabs vial as a tube for the slants, and make another again when the tube arrive? The whitelabs vials look very sturdy and seem to be able to take the heat from pressure cooking it. I'd like to make a slant of the yeast before i use it as i only ordered 1 of each strain.

thx for the replies

greenxpaddy

Re: Making Agar Slants (Slopes) - In Pictures

Post by greenxpaddy » Mon Oct 17, 2011 8:46 am

Here's a couple of failures from my August 2011 production of 15. these have been stored at room temperature since in a sealed tupperware. The infection was not visible in the first few weeks. As a result I am guessing each was from just one cell? I don't tape my tubes but maybe I should...If they are not perfectly airtight I am guessing there is a chance a smaller mould spore around 1 micron diameter can enter through Brownian motion? More likely they did not heat perfectly uniformly in the pressure cooker. Need to cook for longer!

Image

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Re: Making Agar Slants (Slopes) - In Pictures

Post by jmc » Mon Oct 17, 2011 9:49 am

greenxpaddy wrote:Here's a couple of failures from my August 2011 production of 15. these have been stored at room temperature since in a sealed tupperware. The infection was not visible in the first few weeks. As a result I am guessing each was from just one cell? I don't tape my tubes but maybe I should...If they are not perfectly airtight I am guessing there is a chance a smaller mould spore around 1 micron diameter can enter through Brownian motion? More likely they did not heat perfectly uniformly in the pressure cooker. Need to cook for longer!

Image
How long did you cook (at pressure) for?

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