Lazy fermentation – Should I pitch a new yeast pack?

[Agentgonzo]

Other things that people have mentioned before that may help could be too re-rouse the yeast by shaking/swirling your fermenter or seven re-oxygenating the wort.

I'm not wholly convinced by either and again I'm no expert and don't know exactly how this affects the yeast. The theory is that more oxygen allows for an additional growth stage of the yeast so you get more and healthier yeast and a more active fermentation. High gravity brewers sometimes go this, though some say to not do it

Similarly, "rousing" the yeast may not actually benefit the fermentation by resuspension of the yeast in the wort (there is plenty in suspension already). I've heard (again, I'm just repeating here with proper knowledge) that it's more to do with letting the dissolved CO2 (which is known to be an inhibitor to the fermentation) escape so that the yeast can more effectively ferment

 

[Meaulnes]

We are now 48 hours after pitching and there seems to be a definite acceleration (slope is now around 30 pts /24 hours). Nevertheless I need to be careful with the monitoring by the Float device that can sometimes be hampered by the foam resulting from the initial oxygenation.

 

[Birdsnestbrewery]

Yes it is exactly this. The manufacturer says optimal temperature is between 15 °C and 22 °C.

I assume you're getting that from the packet. It's odd because this page says 18 to 26 degrees :
https://fermentis.com/en/product/safale-us-05/Sounds like it's going OK now in any case.

 

[Meaulnes]

I assume you're getting that from the packet. It's odd because this page says 18 to 26 degrees :
https://fermentis.com/en/product/safale-us-05/Sounds like it's going OK now in any case.

I think I better increase the temperature by one °C. I already noticed that the advice changes depending on the translation, the packet or the spec. sheet, etc.

 

[Meaulnes]

My fears were well founded about the Float, the last measure has now rejoined the initial curve.

 

[MashBag]

I am thinking a 2c drop will slow the yeast down.

Could think be to much cooling (by the freezer) creating a cold lag that continues to chill after the target temp has been achieved. Tbh it is unusual to ferment in a freezer most often it's a fridge.

I have recently suffered the same problem with a cooling coil. And have had the same effect with heaters that are to big.

Just my tuppence..

 

[Birdsnestbrewery]

Yes it is exactly this. The manufacturer says optimal temperature is between 15 °C and 22 °C.

I assume you're getting that from the packet. It's odd because this page says 18 to 26 degrees :
https://fermentis.com/en/product/safale-us-05/Sounds like it's going OK now in any case.

 

[Foggie]

Is there any way to set the Difference Value (DS). I have an Ink Bird and set DS to 0.5C to try and keep temperature stable.

 

[Meaulnes]

I use an Ink Bird too and the value at which it starts to cool is setPoint +0.3 °C and the value at which its stops cooling is setPoint - 0.3 °C. The trouble is that when the freezer stops cooling (at setPoint -0.3 °C) there is some inertia and the temperature goes on decreasing roughly 2 °C below. This phenomena doesn't exist when stopping heating that is only natural (no heat accumulation).
This phenomena could be minimized if the regulation range was for example +-0.1 °C

 

[Meaulnes]

As the fermentation continued to drag, I added a Mangrove Jack's M21 pack that I had left. Fermentation is good now.
Moreover as the maximum temperature limit of the yeast is more (25 °C) than what I believed (22 °C) and the ambient temperature in my garage this morning is only 22.3 °C I opened the freezer and powered it down. Moreover, the weather forecast is favorable (22 °C) this afternoon. These last days, in the very South West of France, we are lucky to escape the heat wave which hits the countries bordering the Mediterranean.
Next time, if I need cooling, I will try to use a fridge instead of a freezer. Probably the inertia phenomena is less.

 

[Clarence]

Yes it is exactly this. The manufacturer says optimal temperature is between 15 °C and 22 °C.

Yes, it is. So why not let the temperature rise to 22C and then hold it there? US-05 is a pretty neutral yeast and it won't put off-flavours into your beer at the top of its range. In fact it's quite forgiving even if you go into the mid-twenties.
It's a question of preference, but I would have pitched the yeast at the top of the range, to try to cut down the lag time, and started attemporation when the surface of the beer was covered.
But patience is not one of my innumerable virtues.

 

[dad_of_jon]

Yes I think so because rehydration is not changing the metabolic state. This is what the yeast book says (this section is specifically about not reaching expected final gravity):

erm I made my weisen krieg kopf by pitching a higher abv tolerant yeast into wort that was around 7% - I did re-hydrate it though.

 

[Foggie]

See you have switched off the Freezer. I'd done the same with my Fridge in June. The insulation on the Fridge prevented the beer getting too warm.

I have just put my Winter Ale in the Fridge and set controller to help clearing the beer..

There is a setting - Compressor Delay (PT) - 3 mins

Never used it, but I'm assuming this is the time before the cooling circuit comes on and to prevents "knocking" - rapid on/off cycles. Default 3 mins. It can be set upto 10mins.

Increasing DS to 0.5C and the PT may help smooth temperature curve.

 

[MashBag]

I use an Ink Bird too and the value at which it starts to cool is setPoint +0.3 °C and the value at which its stops cooling is setPoint - 0.3 °C. The trouble is that when the freezer stops cooling (at setPoint -0.3 °C) there is some inertia and the temperature goes on decreasing roughly 2 °C below. This phenomena doesn't exist when stopping heating that is only natural (no heat accumulation).
This phenomena could be minimized if the regulation range was for example +-0.1 °C

Absolutely. Seen/had this effecy. Freezer is too much cooling. You can do the same with heating with a heater that's to big (watts)

 

[Meaulnes]

There is a setting - Compressor Delay (PT) - 3 mins

Never used it, but I'm assuming this is the time before the cooling circuit comes on and to prevents "knocking" - rapid on/off cycles. Default 3 mins. It can be set upto 10mins.

Increasing DS to 0.5C and the PT may help smooth temperature curve.

I think this is useless for me as the time for temperature to increase from setPoint -DS to setPoint+DS is huge (around 30 minutes). Probably depends on the quality of the insulation of the freezer.
The only trouble is the inertia of the cooling device.

 

[Meaulnes]

Increasing DS to 0.5C and the PT may help smooth temperature curve.

I don't think so. It will increase the period but the cold accumulation when going from SP+0.5 to SP-0.5 is much bigger than the one when going from SP+0.3 to SP -0.3 Thus the amplitude of the wave will be bigger while the cooling slope (from SP+DS to SP-DS i.e. the slope of the freezer's internal temperature not the slope of the wort temperature) will always be the same. In short, an ampler and longer rise in temperature and a cooling that is just as brutal but also ampler. With a longer prolongation effect due to inertia.

 

[Sadfield]

I monitor the wort's temperature with a Brewbrain Float device (min 17.44 max 17.75) . The setpoint of the freezer temperature controller is 19°C and from what I can see freezer temperature goes up to 19.3 °C and down to 17.2 °C.

Your freezer is perfectly OK. The freezer fluctuation is having very little affect on fermentation, if the wort temperature is ranging from 17.44°C to 17.75°C. That's very stable.

How many litres of wort?

Fermentis say 50 to 80 g/hl at ideally 18-26°C (64.4-78.8°F).

If this is a +20L batch, then in terms of pitch rate and pitch temperature, you are on the limit of their recommendation. Which could easily result in a sluggish fermentation.

Lower temperature results in more dissolved Co2, which in turn inhibits yeast growth.

 

[Meaulnes]

Your freezer is perfectly OK. The freezer fluctuation is having very little affect on fermentation, if the wort temperature is ranging from 17.44°C to 17.75°C. That's very stable.

How many litres of wort?

Fermentis say 50 to 80 g/hl at ideally 18-26°C (64.4-78.8°F).

If this is a +20L batch, then in terms of pitch rate and pitch temperature, you are on the limit of their recommendation. Which could easily result in a sluggish fermentation.

Lower temperature results in more dissolved Co2, which in turn inhibits yeast growth.

For which gravity is the Fermentis recommendation given? My wort is at 1.048 (20 l). I think you are probably right. As for the temperature fluctuation you may also be right.

 

[Sadfield]

For which gravity is the Fermentis recommendation given? My wort is at 1.048 (20 l). I think you are probably right. As for the temperature fluctuation you may also be right.

They don't specify.

You could try this pitch rate calculator, though.

https://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/

 

[MashBag]

freezer stops cooling (at setPoint -0.3 °C) there is some inertia and the temperature goes on decreasing roughly 2 °C below.

That's a 2°c fluctuation, that yeast won't like.