Aeration of Starter,...NOT Wort,...Jamil ?

[NumbSkull]

So. My O2 regulator & bottle & SS stone should still be used? I blast the hell out of the starter & the wort. But never more than once. What is the proper practice?
I do my starters like this:
Click here

Thanks,
Chris

BTW... I'm new. Hi all!!!

Peter? Peter Brady? Is that you?

Sorry I could not resist. Welcome.

Mort

[KillerRx4]

If harvesting or repitching yeast from the trub of primary ferment is frowned upon. Does that mean that doing the same deal with a starter is going to give the same inconsistent yeast?
ie. Building a starter up to say 2Lt then bottling a portion of that yeast for later use.

[blurry6]

Eric!

Thanks for the response, I really appreciate it and the articles your writing for BeerTools! I'm just about to start a 'build-up' of yeast for a monster beer I'm planning (1.082 OG). Here's my plan in a nutshell:

boil up 2.5-liters of 1.040 hopped wort, cap it in a couple erlenmeyer flasks and set aside to cool to 68F - this 2.5-liters is going to be my 'wort supply' throughout the build-up. I went to MrMalty.com and figured it would take 280-billion cells, or 2.5 liters of starter to hit the recommended cell-count. I used 'continous aeration' in the settings,...not sure if this was right, but it looked like the closest thing :/

Once cooled, take 100ml prepared wort, aerate with aquarium pump/stone/filter for 20 minutes and after that, dispense into sanitized growler (yeast incubator), pitch Wyeast 1056 smack pack (swollen) into 100ml starter in growler, cap with airlock, and wait 'til tomorrow,...should I dispense 100ml into a 'third' container to aerate it, or can I aerate in either the erlenmeyer flask (wort supply), or the growler (yeast incubator) without any adverse affects?

Next day, dispense 200ml of prepared wort, aerate it, and add to 100ml of original wort in growler,

Next day dispense 400ml of prepared wort, aerate it, and add to 300ml in growler.

Next day dispense 800ml of prepared wort, aerate it, and add to 700ml in growler.

Next day dispense 1000ml of prepared wort, aerate it, and add to 1500ml in growler for a whopping grand total of 2500ml of starter! Whoohoo!

Next day,...BREW DAY!!! Whip up my batch and pitch in the starter,...not sure if I should 'decant' off liquid, or just toss it all in,...Smile

Let me know how this sounds,...Again, keep up the great work!

Ryan
Mill Creek, WA

[madmacaw]

"On a homebrew scale do you advocate washing the yeast that is harvested before reuse?"

I assume that you are referring to "rinsing" the slurry as "yeast washing" is actually a process that uses either chlorine dioxide or acid plus water to elimininate bacteria/mold/wild yeast in a slurry. The latter is only used in emergencies when a specific yeast is unavalable as a fresh pitch and the harvested one is contaminated leaving no other options. This proceedure kills a certain amount of yeast and can compromise the ability of those that are weak. So, it certainly is avoided if unnecessary.

If you harvest the yeast from the secondary or tertiary, there is nothing that needs to be rinsed out of the yeast, so rinsing is unnecessary. Any additional steps attempting to manipulate the slurry increases the chance of contamination greatly. Rinsing should always be avoided.

"And since the yeast that has settled out after primary fermentation has "has petered out" do you recommend cropping yeast from the top of the fermenter during fermentation instead of taking it from the bottom afterwards?"

Well, I ran an open fermentation brewery for 3 years and in that case I had to crop when not pitching new because my fermenter bottoms were flat. This is the only circumstance where I recommend that cropping be undertaken. Cropping risks contamination and also selects for some interesting characteristics that are too involved to mention here. Not all of them are good... for one you cannot reuse yeast harvested this way in as many repitches as that that is harvested from a seconday or tertiary vessel. I assume you are asking this question because you want to harvest in the primary.... again, avoid this if at all possible. There will be trub entrained in the krausen that is best avoided as well as the afformentioned risk of infection via handling. Stick with the safe, tried and true practice of harvesting in the secondary or tertiary.


"And man do you ever need to be on another Sunday Show."

I'd do another one if they wish... I figure that they are satisfied with the huge pool of West Coast brewers and what they can offer, so they may already have a full plate.

[madmacaw]

[quote="chrisknight"]So. My O2 regulator & bottle & SS stone should still be used? I blast the hell out of the starter & the wort. But never more than once. What is the proper practice?
I do my starters like this:
Click here

Thanks,
Chris


Yes, just don't pitch the yeast in until you are done with the O2.

[madmacaw]

"...boil up 2.5-liters of 1.040 hopped wort, cap it in a couple erlenmeyer flasks and set aside to cool to 68F..."

There is no need to use that much malt in the starter.... you want reproduction, not fermentation. Starter solution only needs to be around 5 deg. plato if you are using a daily stepping method.

Do you have a pressure cooker (or access to one?). If so there is a real easy way to prepare a large amount of sterile starter solution that stores indefinitely:

Get some XL-DME, some yeast nutrient, a small amount of high alpha hops, some pint sized canning jars, canning bands and lids. Put enough XL-DME into the jar (no need to mix it) to yield 5 deg. plato per pint. Put 1/8 tsp. nutrient and 3 hop pellets in the jar and fill with warm water. Put the lid and band on and shake the jar a couple of times. Repeat until all the jars are filled. Place the jars in the pressure cooker and once the rocker is rocking (or whatever relief device is present) or if you have a pressure cooker with a pressure gauge (preferred) and it indicates 1 bar of pressure (~15 PSI), cook the jars for 20 minutes. Take the cooker off the burner and let cool until the pressure cooker lid can be removed. Remove the jars carefully, tighten the bands and allow to cool to room temperature. Repeat for the remaining jars.

This method yields as much sterile starter solution as you would like to make and can be stored at room temperature and will remain sterile indefinitely.

When you need to make starters, wash your hands really well, rinse them off with alcohol, take the band off a jar and wipe the lid and sides down with alcohol. Open the lid and pour into a STERILE erlenmyer flask. You can sterilize a rubber bung, glass airlock, stainless steel aeration stone, .45 micron air filter, air tubing, stir bar (if you are using a stir plate), small piece of foil and and erlenmyer flask in the pressure cooker the same way as the jars. After cooking, remove the flask and foil and allow to cool with the sterilized foil sealed over the top of the flask. If you let all of the other equipment cool while still in the cooker with the lid on, they will remain sterile long enough to use within the day.

The idea is to use as few flasks as possible while volumizing the culture. The first should be double the size of the pitched culture. (100 ml of yeast + 100 ml of starter solution = 200 ml, so use a 400 ml flask). Put the starter solution in and if using air, NOT O2, put the yeast in, snake the stone's stem through the bung, bung the flask, hook up the tubing and air filter, attach to the pump and turn it on. Don;t worry that the bung hole is not sealed, air will be going outward so there is no potential for contamination. If using O2, put the starter solution in the flask and aerate for 30 seconds. Remove the stone, add the yeast, bung the flask and put the airlock on. The airlock should be filled with either isopropyl alcohol or vodka.

On day 2, pour the first flask into a sterile one that is 2 times the volume of the first... ie... in this example, 800 ml (they don't make these, so 1,000 ml will have to be used. Then add 200 ml of starter solution and follow the same closure instructions as applies for your situation above.

On day 3 you just need to add 400 ml to the day 2 flask's contents as the total liquid volume will be 800 ml.

On day 4 transfer the day 3 flask to a 3,000 ml sterile flask's contents (these use larger bungs so you will have to get one and sterilize it) and add 800 ml of starter solution. Your total liquid volume will now be 1,600 ml.

Continue to volumize over subsequent days until you reach your targeted 2,500 ml volume. In a perfect world (or at least a well equipped one) you don't actually produce starters by liquid volume, you do them by cell count. If you do continuous aeration and use a stir plate it is possible to produce the same cell count in a significantly lower volume of liquid. If you have a hemocytometer and a microscope to allow you to count the cells, great, otherwise proceed as above.

This example requires 1- 400ml erlenmyer, 1- 1,000ml erlenmyer and 1- 3,000ml erlenmyer.

If you have to wait to pitch this starter (it is best to pitch it the day after the last starter solution addition), simply bung it with and airlock filled with alcohol or vodka and place it in the fridge. They will go dormant, so when you do need to use it allow it to warm up to room temperature and then pitch it into your wort. Whatever you do, don't allow them to ferment out the last starter solution addition, instead chill it ASAP to 32 deg. F. This will markedly slow down their metabolism and preserve the viability and vitality of the starter you have produced. If you allow them to ferment and flocculate they will begin glycol synthesis in preparation for long term dormancy. This will increase your lag time if allowed to take place.

Hope this was clear enough and helpful!

[crazymonkey15]

If you harvest the yeast from the secondary or tertiary, there is nothing that needs to be rinsed out of the yeast, so rinsing is unnecessary.

Eric,

Do you find that the flocculation of the yeast changes if you harvest from the secondary or tertiary?

[madmacaw]

Well... can't say that I have noticed any changes over time when using secondary/tertiary harvested yeast. If their floccing ability was effected it would not be due to the harvest point but rather that they had mutated in their overall performance. Down is still down, so as long as laws of gravity don't change, it would have to be due to some other factor. Remember, yeast are not motile... their movement is due to the rise of CO2 and convection within the wort. So, that means that once both have ceased and the yeast have driven the wort to terminal, they should floc unless they are of a non-flocculant strain, which is actually a misnomer, they will floc eventually. Look at a hefe or a Wit that were not treated with gallotannins (becoming increasingly common) that have sat for a 2-3 months. They will have or be close to dropping bright.