From Slant To Starter - In Pictures

Share your experiences of using brewing yeast.
Wolfy

From Slant To Starter - In Pictures

Post by Wolfy » Thu Jul 15, 2010 3:27 pm

As with most things yeast related, there are many ways to achieve the same result, but here the process I use to reculture yeast from a slant and grow it up to a starter of suitable pitching volume.
(I did post this on my local HB forum, but thought it might be useful here too.)

In this example I'm using a 6m old home-made slant of Wyeast Kölsch yeast (2565) and I wanted to make a starter that was 2L in volume.
The starter was stepped up from about 15ml, to 100ml, 400ml and then 2L.

First step was to let the slant come up to room temp, gather the ingredients and clean and clean/sanitise everything:
Image

The saved wort I had kept in the fridge for a couple of months was a bit gunky, so I made the starter wort by boiling about 175g of LDME (and some yeast nutrient) in a little more than 2L of water - aiming for an OG a bit above 1.030.
While the wort was still boiling hot I carefully tipped it into the various containers, topped them with aluminum foil and left them to cool:
Image

The 15ml test tube of wort was quickly cooled in some cold water and then added to the slanted yeast.
Using a (plastic) inoculation loop I carefully scraped the yeast from the surface of the slant, trying to remove all the yeast but leave the solid agar mix behind:
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After tipping the 15ml wort and yeast back into the clean test tube, I kept it on my computer desk, so I'd be reminded to shake it often.
The temperate was generally about 20C and the stater was allowed to ferment out for 24 hours, before stepping up to 100ml:
Image
There is already a small layer of yeast on the bottom of the test tube.
At this stage due to the very small volume of beer a smell/taste test is not going to tell you much, as I suspect there were a few dead yeast cells scraped off the slant.

The 100ml starter was put onto my el-cheapo DIY stir plate and allowed to ferment out for another 24h, before stepping it up to 400ml:
Image
The foam on the yeasty-starter on the left is from yeast fermentation, and the plain wort on the right from me shaking the crap out of it for about 15 mins before pitching the yeast.
(I had a little left over wort so I added some agar agar and made the new blank slants that can be seen in the background.)

After another 24h on the stir plate, the 400ml starter had created a nice layer of yeast, which I left to settle out for a little while so I could take a taste/smell sample:
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Kölsch yeast is not the nicest tasting stuff so I wanted to try to sample some beer without too much yeast in it. :)

After it had passed the taste-test it was pitched into the final 2L volume:
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The yeast was still crawling out of the top of the flask after 24 hours, so I left it on the stir plate for another day to let it complete fermenting.
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The 9l square plastic container may look ugly, but there is no way the yeast can over-flow it and short out the electronics in the stir plate. :)

After one more day - this time in the fridge:
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Any yeast that did not escape in the previous step settled to the bottom of the flask:
Image
The spent beer is now ready to be decanted, then the yeast will be pitched into a batch of beer.

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Bobba
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Re: From Slant To Starter - In Pictures

Post by Bobba » Thu Jul 15, 2010 3:59 pm

Great stuff Wolfy! Suddenly I'm tempted by slants again :D You've made it look soooo easy! haha
That's a good move making all the volumes of wort in one go. Every time I've done it (from bottle conditioned beers only, not slants), I've boiled some wort up every two days, meanings it becomes quite a drag.
Where's the best tutorial to make your own stir plate?
Do you find santiser is enough for starters? I've always boiled up the contents in the vessel to make sure it's sterile (well almost)

FV: -
Conditioning: AG34 Randy's Three Nipple Tripel 9.2%, AG39 APA for a mate's wedding
On bottle: AG32 Homegrown Northdown ESB, AG33 Homegrown Cascade Best
On tap: -
Garden: 2x cascade, 2x Farnham whitebine (mathon), 2x northdown, 1x first gold

smdjoachim

Re: From Slant To Starter - In Pictures

Post by smdjoachim » Thu Jul 15, 2010 4:04 pm

=D> well done
Now i see why they are called slants #-o

leedsbrew

Re: From Slant To Starter - In Pictures

Post by leedsbrew » Thu Jul 15, 2010 4:30 pm

Very cool pic tut there matey. Thanks LB

Wolfy

Re: From Slant To Starter - In Pictures

Post by Wolfy » Thu Jul 15, 2010 4:41 pm

Bobba wrote:Where's the best tutorial to make your own stir plate?
Do you find santiser is enough for starters? I've always boiled up the contents in the vessel to make sure it's sterile (well almost)
The way I did the stir-plate is too simple to need a tutorial. ;)
Very simple and easy to make:
4x small flat-round rare-earth magnets (get them from Ebay or similar very cheaply) super-glued to opposite sides of the hub of the fan, about the same distance apart as my stir-bar is long.
6 to 12V power adapter (any old one will do, probably have some old ones hanging around at home, from old mobile phones, old modems etc)
12V speed controlled computer fan - they should be available from most computer shops. Mine has some pretty LED's simply because that was what I had already, looks something like this:
Image
Then all you need is something to mount it on, you can be as creative (or in my case cheap) as you like, I just used an old plastic computer HDD bay fan mount thing.

(As you can see) the fan has a dial for adjusting the speed, so it already has the built in electronics, pot etc, all you need to do is connect up the 12V power supply, so while soldering skills are useful, they're not essential.
It's not flash or fancy, but it works and does the job, some people get creative and create all sorts of fancy circuits and add all sorts of electronics, but the magnets will cost you virtually nothing, the fan will cost about as much as a bottle or two of beer, the stir bar about one more bottle of beer, and the rest you probably already have at home.

The end result is something like this:
Image
I just added the extra on/off switch so I didn't have to turn it off at the power point all the time, and the 9L plastic container makes it 'spill proof' since StirPlate V1.0 created some nice fire-works in my lounge room when the starter over-flowed and shorted out the power supply. ;)
(As with anything you read online, please use this information at your own risk and don't blame me if something goes wrong, but I wouldn't mind a visit to the UK one day, so if you wanted to extradite me, I may not object.)

I try to get the slants as sterile as possible, but with the starters I just dose the containers with StarSan and then add the wort boiling-hot and cap it immediately, with the theory that the boiling wort will help sanitise/sterilise to an extent. Since I don't have lab conditions, and I can't help but test/smell/check the starter while it's growing, so more than that is probably overkill. :) I also tend to be a little conservative with my step-up-volumes (some people would go slant-50ml-1.5L) so that probably helps the yeast colonise the wort more easily before any infection sets in.

JackA

Re: From Slant To Starter - In Pictures

Post by JackA » Thu Jul 15, 2010 5:11 pm

Thanks for the picture tutorial - very useful :)

Quick question: how do you know when the yeast is ready to be stepped up?

Wolfy

Re: From Slant To Starter - In Pictures

Post by Wolfy » Thu Jul 15, 2010 6:05 pm

JackA wrote:Quick question: how do you know when the yeast is ready to be stepped up?
Most people suggest you step up while the yeast is actively fermenting during the 'high krausen' stage.

However, especially with small starters and depending on the type of yeast you have, it's often difficult to tell when that is, since there is often no visible sign of aggressive fermentation.
I usually take an easier approach: If i notice signs of fermentation, usually by sight or smell, I'll step up the starter after 24 hours.
That way I always remember when it needs to be done, and it's easy to plan how long creating the starter will take which is especially useful if you have a set day for brewing, like on the weekend.

In theory (if it was under sterile conditions) we are only looking to grow yeast, so it could be stepped up as soon as the oxygen and nutrient supplies required for yeast-reproduction are depleted and fermentation begins, however in a home situation it may be beneficial to allow the yeast to ferment out (at least a bit) to help inhibit the growth of any unwanted bacteria or the like.

In regard to the last step of the process, again many people will suggest you pitch the yeast into your batch of beer-wort when it's most active, however I find this has two main drawbacks:

Firstly I prefer to use my starters to grow yeast and not make good beer, the fermentation temperature and the stir plate are both aimed at that, meaning the beer produced in the starter will most likely have numerous off-flavours that you'd not want in your final beer. Pitching when the yeast is most active will require pitching the entire starter and hence adding the off-flavoured beer-starter to your main batch, which is something I consider undesirable.

Secondly, I'll create my starters using either LDME (like I did in this case) or by using saved-wort from the last batch of beer I made. In both cases, since I use AG procedures, and very rarely brew two similar beers in a row, the starter wort will be different (often quite different) to the beer I'm pitching the yeast into. If the yeast is pitched directly when it's most active, it may not have the correct enzymes and may be stressed by the sudden and drastic change of conditions (think of a freshwater trout suddenly thrown into sea water).
By letting the yeast ferment completely (in this case the last step took 48 hours until I could see no more signs of active fermentation) the yeast build up their glycogen and trehalose reserves, they will then flocculate out (with the aid of time in the fridge) so that the spent beer can be decanted and only the yeast pitched into the batch of beer. In addition the yeast's reserves should allow them to wake up and start adapting to the new wort quickly and easily and they can create whatever enzymes they need for the new conditions.

Having said that, there are many different approaches when it comes to yeast and starters, and many of them work very well - yeast are robust little buggers and will do well even if we don't treat them as good as we could. So I don't think there is any one right or wrong way to do things, most of the things I've suggested work for me, but that's often just because they are easy or fit my procedures and equipment, so I try to balance that with the various bits of knowledge and various different methods and suggestions.

boingy

Re: From Slant To Starter - In Pictures

Post by boingy » Thu Jul 15, 2010 6:17 pm

Stir bar question: what do you use for a stir bar?

Wolfy

Re: From Slant To Starter - In Pictures

Post by Wolfy » Thu Jul 15, 2010 7:07 pm

boingy wrote:Stir bar question: what do you use for a stir bar?
A stir bar ... purchased from a laboratory/science supply type company.
It's a bit out of focus, but you can see it in the picture of the yeast in the bottom of the flask in the only the photograph taken from underneath the flask.

The ones with the pivot (ring in the middle) as shown on the Wiki page (apparently) make alot of noise, so I use the plain white Teflon coated ones, pretty much like most of them on the Google Images search for stir bar and they look mostly like this:
Image

I got a few sizes, because what works best seems to depend on the magnet spacing and how the stir plate is designed, but the one I generally use - with the cheap-ass stir plate shown above - is about 23-24mm in length.

Others have used various other things including those oval-shaped magnets or even a sanitised steel bolt. :)

adm

Re: From Slant To Starter - In Pictures

Post by adm » Thu Jul 15, 2010 10:43 pm

Nice tutorial! Thanks

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Bobba
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Re: From Slant To Starter - In Pictures

Post by Bobba » Thu Jul 15, 2010 10:49 pm

Brilliant thanks a lot Wolfy! :D
According to mrmalty pitching rate calculator, a stir plate should halve the size of the starter compared to me giving a shake when i remember. I did notice a huge improvement in the fermentation time when I got the pitching rate right o the last batch.
Looks like a good project for a saturday afternoon that (hopefully will be a bit more succesfful than my relay circuit bodge last week which still trips the fuse for my flat electrics :?

FV: -
Conditioning: AG34 Randy's Three Nipple Tripel 9.2%, AG39 APA for a mate's wedding
On bottle: AG32 Homegrown Northdown ESB, AG33 Homegrown Cascade Best
On tap: -
Garden: 2x cascade, 2x Farnham whitebine (mathon), 2x northdown, 1x first gold

Wolfy

Re: From Slant To Starter - In Pictures

Post by Wolfy » Fri Jul 16, 2010 6:22 am

Bobba wrote:Brilliant thanks a lot Wolfy! :D
According to mrmalty pitching rate calculator, a stir plate should halve the size of the starter compared to me giving a shake when i remember. I did notice a huge improvement in the fermentation time when I got the pitching rate right o the last batch.
Looks like a good project for a saturday afternoon that (hopefully will be a bit more succesfful than my relay circuit bodge last week which still trips the fuse for my flat electrics :?
When you look at some of the 'scientific information' in regard to the differences in cell count when using different methods of aeration (like this for example) where their tests give numbers like 50million/ml for a shaken starter and 250million/ml for a stir plate, and compare that to the cost and simplicity of building your own stir plate - even if their science is not totally correct the stir plate should still make a big difference.

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Re: From Slant To Starter - In Pictures

Post by Jolum » Fri Jul 16, 2010 9:23 am

Nice post Wolfy =D>

Out of interest has anyone got a plate stirrer working with a standard gallon size demijohn? I've got 14 of the buggers and couldn't find one with a flat enough bottom :( Since then I've been trying to find a reasonably priced 2-3L conical but the prices they want for them is ridiculous.
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Re: From Slant To Starter - In Pictures

Post by beer taster » Fri Jul 16, 2010 1:25 pm

Jolum wrote:Out of interest has anyone got a plate stirrer working with a standard gallon size demijohn? I've got 14 of the buggers and couldn't find one with a flat enough bottom :(
One (out of 6) of my 5 Litre demijohns works on my stir plate. but I normally use a smaller 2 Litre one
Image Image

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Re: From Slant To Starter - In Pictures

Post by Jolum » Fri Jul 16, 2010 1:28 pm

beer taster wrote:
Jolum wrote:Out of interest has anyone got a plate stirrer working with a standard gallon size demijohn? I've got 14 of the buggers and couldn't find one with a flat enough bottom :(
One (out of 6) of my 5 Litre demijohns works on my stir plate. but I normally use a smaller 2 Litre one
Image Image
Lucky sod :lol:

I must say, I've never seen a 2L demijohn on sale at any HBS.
"Everybody has to believe in something…..I believe I’ll have another drink." - W.C. Fields

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