Bohemian Lager Yeast (Mangrove Jack's M84)

[AzfromOz]

Hi,

Am brewing a Kolsch from a recipe. The recipe called for specific Wyeast or Whitelabs kolsch yeast strains that aren't available near me, so I decided to go for a German ale type yeast, also without luck. Settled on a Bohemian lager yeast, given that Kolsch beers are similar to lagers. That yeast wants to ferment at the 10 - 15 degree temperature range. The recipe wants the wort to ferment at 21 degrees, which to me seems high for the yeast type even if I had the recommended yeast. Anyway, fermentation started within 6 hours at 21 degrees and is still happily bubbling away near 48 hours.

Question: given the yeast type, should I drop the temp to, say, 15 degrees after say, day four, and then lager it for a couple of weeks, or just let it ride it out at 21 degrees and bottle and condition once fermentation has stopped. Pros and cons of either?

cheers

 

[goid]

I haven't used bohemain lager yeast, but I would bring it down to the recommend range for the yeast now. Leave it within that range for 3 weeks than lager for a couple.

 

[earle]

Go with the temp recommended for the yeast. The recipe yeast instructions aren't really valid for you anymore as you have changed the yeast.

On Kolsch yeasts though - I usually start off at about 14 for a week, then increase to above 20 for another week for a yeast clean up before cold crashing. Sounds like your recipe might have just gone with a recommended temp for a single temp ferment.

 

[Drewski]

Would drop the temp ASAP, Instructions you read are for a top fermenting Ale yeast not a lager.. Also with a dry lager yeast usually two packets are suggested to get the initial yeast count. You did start high temp wise which some people do to get yeast kicking with lagers, but would drop to recommended temp which would be between 12-15deg.

 

[AzfromOz]

Thanks, everyone, for the tips. Have dropped to 15 degrees now as per yeast instructions. Will sit for one week at that temp and then see what the beer is doing.

Cheers!

 

[Bribie G]

It's a really good yeast that attenuates and cleans up well, I used it with their Pilsner kit and a pack of brew enhancer with dark dried extract to make a sort of Vienna Lager, and it was hard to pick as a kit n kilo.

 

[fraser_john]

It's a really good yeast that attenuates and cleans up well
<snip>

I use it in a large variety of lagers and it is an excellent, clean yeast. So good in fact I bought the soon to be expired 500gm pack($35 from memory!) from Craftbrewer and repackaged into 25gm vac sealed bags. Though soon to expire, I have not seen any difference in its quality.

 

[Bribie G]

Off topic but I reckon that if a company such as Mangrove Jacks, any company, had introduced a full range of specialists dried yeasts ten years ago, then Wyeast and Whitelabs would have been really up against it.

Liquid yeasts are great, but I think most of their attraction until now is that the dried yeast market was almost in a fossilized state until recently. Notto. US-05. S04.Three lager yeasts and a German ale or whatever, end of story.

To my surprise I've been having great results with their Northern Brown, Burton Union and Bo Lager.

Go Mangrove

 

[AzfromOz]

Now to selfishly put the focus back on me, I realise I just did something stupid. I turned the temperature control down to 15 in one hit, rather than stepping it down, meaning the temperature crashed to 15 and all of the yeast, presumably, died. Within an hour, when I first checked, all fermentation had ceased. So.... should I try to salvage the beer by putting another packet of dried yeast into the fermenter? It was fermenting happily until I dropped the temperature, so I assume there's still sugars in there for the yeast to convert. Or should I just let it sit for two tot three weeks at 15 degrees and see what happens?

Any advice appreciated!

cheers

 

[Rocker1986]

What is the size of your batch? It probably wouldn't have dropped the liquid (wort) temp that far in only an hour. It takes a few hours normally, if it's a 'normal' ~23 litre batch.

 

[verysupple]

The yeast won't be dead, it would have just floccuated and dropped to the bottom. If you keep the temp. constant and keep rousing the yeast then eventually (I dunno, maybe half a day, a day...) they should start fermenting again. You just put 'em to sleep, that's all.

 

[AzfromOz]

It's a 21l batch. Maybe one hour after was a stretch but definitely within two hours.

How does one go about rousting yeast? Temperature will remain constant due to the keg king regulator and my grandma's fridge.

 

[Bribie G]

Lager yeasts at their normal operating temperature don't produce much krausen and appear to be inactive. Give it a few more days and you should see activity, such as a growing layer of yeast on the bottom of the fermentor.

 

[indica86]

The yeast won't be dead, it would have just floccuated and dropped to the bottom.

Lager yeasts are bottom fermenting so that is where they should be.

 

[indica86]

To my surprise I've been having great results with their Northern Brown, Burton Union and Bo Lager.

Go Mangrove

The British Ale is brilliant, I am a big fan.

 

[AzfromOz]

Lager yeasts at their normal operating temperature don't produce much krausen and appear to be inactive. Give it a few more days and you should see activity, such as a growing layer of yeast on the bottom of the fermentor.

Even with no activity in the airlock? Been a while since I checked as I'm offsite, but the airlock went from happy activity to nothing last time I checked.

Will check the yeast cake when I get back for reference purposes.

Cheers

 

[Barge]

I don't want to be a party pooper but...

I brewed a BoPils late last year with the m84 and buggered up the settings on the fridge. Pitched it warm (19/20) then tried to bring it down quickly. Long story short, I now have a batch that is almost undrinkable. Ethyl acetate like nobody's business. I'm hoping it will clear up but it's been 2 months now and it isn't getting much better.

Hopefully your experience is better. My advice is to make sure you taste it before racking off the yeast cake as I may not have left it long enough to absorb the off flavour.

 

[Rocker1986]

Airlock activity doesn't really mean much... it probably stopped due to the change in pressure inside the FV from the temperature drop. However, look for signs of activity in the brew itself such as a small krausen, or condensation on the inside of the lid etc. or even take a quick SG sample to see if it's dropped.

 

[AzfromOz]

I don't want to be a party pooper but...

I brewed a BoPils late last year with the m84 and buggered up the settings on the fridge. Pitched it warm (19/20) then tried to bring it down quickly. Long story short, I now have a batch that is almost undrinkable. Ethyl acetate like nobody's business. I'm hoping it will clear up but it's been 2 months now and it isn't getting much better.

Hopefully your experience is better. My advice is to make sure you taste it before racking off the yeast cake as I may not have left it long enough to absorb the off flavour.

Thanks. How long did you let it sit on the yeast cake before racking? Mine's only at day three now so I intend to leave it for at least another couple of weeks. Long time to wait just to see if you've stuffed your beer!

Airlock activity doesn't really mean much... it probably stopped due to the change in pressure inside the FV from the temperature drop. However, look for signs of activity in the brew itself such as a small krausen, or condensation on the inside of the lid etc. or even take a quick SG sample to see if it's dropped.

No krausen yet, but possibly the smallest amount of movement in the airlock - both sides now no longer dead even....

Will take a gravity sample in a couple of days.

Cheers!

 

[Barge]

I can't remember how long exactly but it was only in primary for around 7-10 days. I did a diacetyl rest and figured that lagering in secondary would be enough to clean it up.