Pitching a second packet of yeast

[Bald Head Brewery]

Afternoon all,

Just a question, I've heard yeast can 'die' if you pitch it too hot. With both my brews I've pitched at 18 and had no issues but I'm wondering if this were to occur and the yeast didn't ferment can you save it by adding a second lot of yeast?

Regards

BHB

 

[Adr_0]

Yep, but you want to be quick... and it may that be that the yeast survives, but throws a heap of esters and some nastier flavours like acetaldehyde or fusel alcohols.

Basically you should be aiming for signs of fermentation within 4-12hrs of pitching. Longer than 24-36hrs and something else is likely to come into the mix and spoil your beer. So you should make sure that you have enough yeast (generally two packets of most strains, despite what the instructions say) and have it at the right temperature to start with.

 

[mtb]

Basically you should be aiming for signs of fermentation within 4-12hrs of pitching. Longer than 24-36hrs and something else is likely to come into the mix and spoil your beer. So you should make sure that you have enough yeast (generally two packets of most strains, despite what the instructions say) and have it at the right temperature to start with.

I've gotta disagree with you on that. All these factors depend on the particular strain in use. A single pack of dry US05, for example, often will take 24hrs to form krausen but hits FG within 5 days.

 

[Adr_0]

I've gotta disagree with you on that. All these factors depend on the particular strain in use. A single pack of dry US05, for example, often will take 24hrs to form krausen but hits FG within 5 days.

Pfft, what would you know? Not like you can brew a comp-winning IPA...

You know, I was going to say "except for US-05" but then even that benefits from more cells, having a faster take-off and hitting FG in 3 days... but of all the strains it definitely seems to be one of a handful that can get away with one pack. M44 and S-04 don't fall into that category, with many many others.

 

[mtb]

Pfft, what would you know? Not like you can brew a comp-winning IPA...

You know, I was going to say "except for US-05" but then even that benefits from more cells, having a faster take-off and hitting FG in 3 days... but of all the strains it definitely seems to be one of a handful that can get away with one pack. M44 and S-04 don't fall into that category, with many many others.

said IPA was actually fermented with US05.
I guess the basis of my point is, if your ferment doesn't kick off at all, it's just as likely to be yeast quality as it is pitch rate. There are plenty of factors to consider. You're right though - there are many strains which need a couple packs.
@Bald Head Brewery which yeast did you use, and where did you get it? If the shop doesn't refrigerate it, stop going there.

 

[2cranky]

I've been using starters lately and you do get a better idea of viability that way.
You can taste the beer off the starter to see if its okay.
They also take off a bit quicker.
I usually pitch around 20-22 and drop it down to 18 straight after pitching.
Used a White Labs California Ale Yeast (WLP001) and made enough for a 23L double IPA and a 23L regular IPA and both were bubbling away at 16 hours after pitching. The double got a bit too excited and made a bit of a mess!

 

[Bald Head Brewery]

Krausen, just had to google that. I never knew the froth on top had a name. Do some yeasts give a bigger krausen then others? Love this education stuff.

 

[Danscraftbeer]

Everything about beer has a name. Many German. And yes every yeast has different characters and behaviours.
All part of the fascination.

 

[Bald Head Brewery]

Everything about beer has a name. Many German. And yes every yeast has different characters and behaviours.
All part of the fascination.

I love the differences in beer making. Actually I just love beer

 

[Danscraftbeer]

Join the club haha. Anything I haven't tried is something I want to try.
I wish I could get that through to megaswill drinkers. "Oh I can only drink Melbourne" "Oh I can only drink Vic Bitter" "Nah I can only drink Carlton Draught" oh well, they just don't get it...

 

[koshari]

Join the club haha. Anything I haven't tried is something I want to try.
I wish I could get that through to megaswill drinkers. "Oh I can only drink Melbourne" "Oh I can only drink Vic Bitter" "Nah I can only drink Carlton Draught" oh well, they just don't get it...

Furphys at least appears to be a good start.

 

[Lionman]

I love the differences in beer making. Actually I just love beer

Mate, I can assure you that you are in the right pace if you love beer.


Wort aeration can also impact lag time of yeast. You want as much oxygen in your wort as possible at the moment you pitch the yeast, This will allow the yeast to multiply to a larger number of cells in a shorter amount of time and result in faster and cleaner fermentation.

The biggest improvement in my beer after temp controlling fermentation came from oxygenating my wort.

Edit- Your wort will have to be pretty warm to actually kill the yeast. close to 50c. If the temperature difference between the yeast in the packet and the wort your adding it to is to great it can stress the yeast though which could potentially cause it to lag, but also make you beer taste not as good. Best practice is to let the yeast warm up to the temp of the wort (or starter/ or water if rehydrating). You want the wort to be at optimal temp within the first few hours, before active fermentation starts.

 

[Bald Head Brewery]

A bit off topic but will running a gas line split for my 2 kegs work alright, both beers are ales.

 

[mtb]

A bit off topic but will running a gas line split for my 2 kegs work alright, both beers are ales.

I split my line across six. It's fine. What you have to be mindful of is leakage though, make sure to use some hose clamps and test for gas leakage. Easiest way I've found to do that is set your reg to a nominal pressure, then close off the bottle. If there is no leak, the nominal pressure shouldn't change over a few hours afterward (or at all, but watch it for a few hours minimum). Do this without a keg connected since beer in a keg could absorb the Co2 and mess with your testing.

 

[Bald Head Brewery]

Thanks bod, will definitely do that. Is it weird working out at the gym thinking about beer.

 

[mtb]

Thanks bod, will definitely do that. Is it weird working out at the gym thinking about beer.

Nah. As long as you're not thinking about other beers while drinking your own. That's just unfaithful.

 

[Bald Head Brewery]

Never dream of that. Faithful all the way

 

[Bald Head Brewery]

Do you lads leave your gas on when not drinking or turn gas off?

 

[mtb]

Depends how confident you are in your line clamps. If you're sure there are no leaks, by all means, leave it on. It'll carb your kegs faster assuming you carb at dispensing pressure like I do

 

[DU99]

i leave my gas on to my kegs..

 

[Lyrebird_Cycles]

You want as much oxygen in your wort as possible at the moment you pitch the yeast

Sorry to be the naysayer but this isn't true.

Firstly, you want enough oxygen for the yeast to be able to make enough ergosterol and fatty acids to survive the alcohol they will generate, generally around 10 - 15 mg/l O2. You don't want more than that, it just invites problems including premature staling. For reference "as much oxygen as possible" is around 40 mg/l under normal conditions.

Secondly, it's obviously better to add the oxygen to the yeast rather than to the wort, so ideally you want oxygen level at pitch to be zero and to add the oxygen after pitching.

I am aware that commercial breweries often add oxygen before pitching but that doesn't make it ideal: in fact it's due to operational considerations including solubility. Adding the O2 in line from castout to fermenter vastly increases the amount that goes into solution, a commercial operation won't accept the 90% loss that's common with home brew setups.

 

[Lionman]

Sorry to be the naysayer but this isn't true.

Firstly, you want enough oxygen for the yeast to be able to make enough ergosterol and fatty acids to survive the alcohol they will generate, generally around 10 - 15 mg/l O2. You don't want more than that, it just invites problems including premature staling. For reference "as much oxygen as possible" is around 40 mg/l under normal conditions.

Secondly, it's obviously better to add the oxygen to the yeast rather than to the wort, so ideally you want oxygen level at pitch to be zero and to add the oxygen after pitching.

I am aware that commercial breweries often add oxygen before pitching but that doesn't make it ideal: in fact it's due to operational considerations including solubility. Adding the O2 in line from castout to fermenter vastly increases the amount that goes into solution, a commercial operation won't accept the 90% loss that's common with home brew setups.

Totally understand this, but for the homebrewer, getting much more than 15mg/l of O2 into solution would take considerable effort and/or waste a lot of O2.

If you're just sticking aeration stone into the wort after pitch, and giving it a squirt of O2 for a minute or two, you wont have any issues. You would have to pump A LOT of O2 through the wort to get close saturation. As you have said, most of it is lost to the atmosphere anyway.

Do you think that excessive 02 is a really a concern for the home brewer using an aeration stone?

 

[Lyrebird_Cycles]

I think it's a minor concern.

When I was using an O2 bottle + sinter setup I had a couple of brews that show evidence of oxidation which I sheeted back to the oxygen. One of them was definitely my fault, I oxygenated the wrong cube for the wrong time.

Where this might be of concern is that I'm talking obvious, "cardboard", lipid oxidation here. More subtle effects such as loss of evanescent aromas would not be evident but the beer would be less enjoyable.

 

[lespaul]

Just something i found looking up the topic:
https://byo.com/bock/item/958-keys-to-aeration-advanced-brewing

Some interesting points based on what you said were:
At sea level and freezing (32 °F or 0 °C) pure water can hold up to 14.6 milligrams per liter (mg/L, equivalent to parts per million, or ppm) of dissolved oxygen
Minimum level is considered to be 5 mg/L, and the optimum demand for oxygen by some yeast strains at higher specific gravities increases to as much as 12–13 mg/L
Major American lager brewers, for example, strive for a dissolved oxygen level of 9-10 mg/L in their wort.
Pitch a large population of healthy yeast and aerate the chilled wort well.

So not sure what you mean by 40mg/L as it says that the higher the SG the less oxygen the wort can hold?

 

[Lyrebird_Cycles]

The stated maximum (~15 mg/l @ 0 oC) is for water in equilibrium with air at atmospheric pressure*.

Henry's law applies, so for O2 at STP the equilibrium point is higher. For O2 under pressure, the equilibrium point is higher again. The Henry's law coefficient reduces with temperature** so at typical pitching temps the equilibria are a bit lower.

As previously, large breweries go for a certain DO2 level due to operational constraints. You actually don't want any DO2 at all, you want the oxygen to be taken up by the yeast.

The presence of sugar limits the solubility of oxygen due to the "salting out" effect, basically dependent on the fraction of volume of the fluid which is water (in which O2 is soluble) vs sugars and salts (in which O2 is not soluble). As a rough round guide, in a normal wort of about 12 oP the O2 solubility will be around 15% lower than that of water. If you are using oxygenation rather than aeration this effect is not important for any practical wort gravity, you will still be able to get enough oxygen into solution.

* I think part of the reason for the confusion is that people are used to solubilities of solids. Solubilities of gases are completely different, best example is that gas solubilities decrease with increasing temperature while solid solubilities increase. This is because they are governed by different mechanisms.

**For this you need the Van T'Hoff equation