2 AGs in one day

Cwrw666 said:

You could of course not bother with aeration at all. Plenty of homebrewers don't, apart from dropping the wort into the FV from a couple of feet, and don't have any problems at all getting fermentation going. I don't even hydrate the yeast anymore.

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Dads_Ale said:

I have done two in one day before and it was a lonnnngggg day. Not planning another one soon :)

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Fore said:

Found time for some left-overs at 21:00; first and only thing I ate all day!

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Fore said:

Yes, on the go from 09:30 to 20:30; not done 2 AGs in a day before, still aching today. 2 of Wheeler's highly rated, Hop Back Summer Lightning and Ruddles Best, 2x 40 pints. Few tweaks here and there, to use up ingredients, as you do. Didn't start off with the idea to do 2, but as the first was finishing up, around 15:00ish, I just moved on to the next.

Targets were hit pretty well. Over-estimated boil off on the first, so tweaked for the 2nd and hit every target, including pH (I treat my water). They have started up well; the yeasts in both are zooming around the fermenters this morning. Sitting at 19, about where I want them at this stage.

I earlier created a sort of step by step brewday check list, and following that makes the whole process progress very easily. Few if any questions arise and nothing is missed. There is none of that "oops I need cooled boiled water right now".

I decided to move back from double batch sparge to single batch sparge. I felt I was getting some astringency coming through, even though I had the temps and pH covered. My BH efficiency with double batch was about 72%. It is 66% with single batch, with a mash efficiency of around 76-78%; I can live with that.

One other change I made was in aeration. I'm pretty sick of the 5-10 minute vigorous stirring, so cut short a plastic paddle and attached it to a drill. Bingo! Rapid effective aeration in no time and no effort. Pretty happy with that.

So, long and action packed, but stress free and very successful. Happy chap.

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Cwrw666 said:

You could of course not bother with aeration at all. Plenty of homebrewers don't, apart from dropping the wort into the FV from a couple of feet, and don't have any problems at all getting fermentation going. I don't even hydrate the yeast anymore.

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DoctorMick said:

You don't need to aerate with dry yeast (strange Steve posted details previously) so it can be unnecessary.

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private4587 said:

I am about to embark on my first AG brew and was wondering if you could give me a run down on the check list you used as I don't want to forget anything as I go along thanks

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Fore said:

Happy to oblige. Everything listed is very specific to my process of course, so just take what you can and redesign for your own setup. My specifics are... I batch sparge. I have a large 40l boiler into which I first measure and treat my total water, then transfer measured volumes to the HLT as I need them. D-1 & D-2 are 1 & 2 days before I start proper. I have a recirc chiller, so need ice. I rehydrate my yeast.

So here my process notes.....

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TheQuokka said:

??? It's not just a clever name, then?

Of course you do. The only time you reduce the need for aeration is when using a starter up towards the optimum number of cells. Double pitching rehydrated good dried yeasts seems to work OK with the aeration or pouring into the FV but fermentation will start quicker and cleaner with a little more.

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TheQuokka said:

??? It's not just a clever name, then?

Of course you do. The only time you reduce the need for aeration is when using a starter up towards the optimum number of cells. Double pitching rehydrated good dried yeasts seems to work OK with the aeration or pouring into the FV but fermentation will start quicker and cleaner with a little more.

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Q. I always aerate my wort when using liquid yeast. Do I need to aerate the wort before pitching dry yeast?

A. No, there is no need to aerate the wort but it does not harm the yeast either. During its aerobic production, dry yeast accumulates sufficient amounts of unsaturated fatty acids and sterols to produce enough biomass in the first stage of fermentation. The only reason to aerate the wort when using wet yeast is to provide the yeast with oxygen so that it can produce sterols and unsaturated fatty acids which are important parts of the cell membrane and therefore essential for biomass production.

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Yeast need a trace amount of oxygen in an anaerobic fermentation such as brewing to produce lipids in the cell wall. Without O2 the cell cannot metabolize the squalene to the next step which is a lipid. The lipids make the cell wall elastic and fluid. This allows the mother cell to produce babies, buds, in the early part of the fermentation and keeps the cell wall fluid as the alcohol level increases. Without lipids the cell wall becomes leathery and prevents bud from being formed at the beginning of the fermentation and slows down the sugar from transporting into the cell and prevents the alcohol from transporting out of the cell near the end of the fermentation. The alcohol level builds up inside the cell and becomes toxic then deadly.

Lallemand packs the maximum amount of lipids into the cell wall that is possible during the aerobic production of the yeast at the factory. When you inoculate this yeast into a starter or into the mash, the yeast can double about three time before it runs out of lipids and the growth will stop. There is about 5% lipids in the dry yeast.

In a very general view:
At each doubling it will split the lipids with out making more lipids (no O2). The first split leaves 2.5% for each daughter cell. The second split leaves 1.25% for each daughter cell. The next split leaves 0.63%. This is the low level that stops yeast multiplication. Unless you add O2 the reproduction will stop.

When you produce 3-5% alcohol beer this is no problem. It is when you produce higher alcohol beer or inoculate at a lower rate, that you need to add O2 to produce more yeast and for alcohol tolerance near the end of fermentation. You definitely need added O2 when you reuse the yeast for the next inoculum.

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Dried yeast is produced in a 'semi continuous' process, where the level of 'food' is supplied depending on the rate at which is it being used up. Oxygen is also provided on an automatic basis. What controls this is the rate of 'fermentation' as defined by the evolution of CO2. If CO2 rises the amount of food supplied is reduced, the amount of oxygen is increased as well, if the CO2 level falls food is increased and O2 decreased.

The likes of Lallemand, Danstar, etc are in the business of growing yeast not making beer so the 'food' is actually a very dilute solution of, hopefully maltose, sugar. The reason for this is that in order to avoid the Crabtree effect, where yeast in a solution of glucose > 4% ~ 1.012 cease aerobic respiration and switch to anaerobic, and get maximum reproduction in the shortest time. Toward the end of the run the gravity of the solution is increased, and 02 supply is turned down at a controlled rate. This forces the yeast to use anaerobic respiration and to 'store' 'oxygen', lipids sterols and ergosterols, and produce trehalose (a storage form of carbohydrate). They then go dormant once the food runs out. 95% of the yeast mass is removed and dried and the process starts all over again.

What does this mean for us as brewers? Firstly the yeast have a source of food - trehalose (very short term supply 15-30 minutes) for the moments after rehydration, hence the reason why you need to pitch your yeast within 30 minutes of rehydration. Secondly they have all the lipids, sterols and ergosterols to allow them to build cell walls for when they divide when we ask them to ferment our wort. . . .

So do we need to oxygenate our wort when using dried yeast?? Technically no, but there are some caveats

Am I intending to repitch this yeast into another beer?

If the answer to this question is yes, then you need to oxygenate, you need to allow the yeast to build up its reserves of lipids sterols and ergosterols to grow in the next batch, you might also want to consider a second burst of aeration before the main fermentation starts (within around 12-18 hours).

Is this yeast a good flocculator?

Or perhaps this should be rephrased as "Is this a lazy yeast?". I'm thinking specifically of Windsor here, but SO4 could be included in this category. In order to get full attenuation, these yeasts do benefit from additional aeration at the start of fermentation.

Am I pitching enough yeast?

Pretty much self explanatory, if you are under pitching, then you will need to aerate, if it is a high gravity ale, then even pitching 'enough' yeast might be considered under pitching. . . combine this wit a lazy yeast and you could be asking for trouble.
So you don't need to aerate your wort when using dried yeast, but it is best practice to do so

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BeerisGOD said:

The worst part is when you've told your misses a finish time

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