# M84 Yeast



## penrithbeerclub (15/7/13)

hi guys, im on my 3rd brew mix. I have used an M84 Mangrove jack yeast on advice from the HB shop due to the temp. with my previous brews, i noticed some bubbles on top of the wort after 24 hours, however with the M84, nothing. I know this is a bottom feeding yeast. My question is, does a bottom fermenting yeast act different to a top feeding standard coopers ale yeast? how will I know its active (outside the obvious bubbles in the airlock)


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## Rocker1986 (16/7/13)

Ignore the airlock. It's not a reliable indicator of fermentation. I've never used that yeast but it is possible that it has a longer lag phase, i.e. takes longer to kick in and show any visible signs of activity. Look for a krausen, or take a reading with your hydrometer after a few days and see if it has changed.


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## yum beer (16/7/13)

Lager yeast will take a while longer to show signs of fermentation.
The krausen will be much smaller and progress slower. What temp did you pitch at and what temp is your FV.


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## penrithbeerclub (18/7/13)

It has activitated since yesterday.

I pitched at 22C and my volume is 23L


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## Droopy (18/7/13)

Excellent news...


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## Lecterfan (18/7/13)

The pitching rate for lager yeasts is different also. Having just downloaded and trawled my way through various .pdf files from Mangrove Jacks, Fermentis etc, the recommended pitching rates of dry lager yeasts in general (if being brewed at lager temps less than 12c) are generally 1gm per litre give or take (fermentis 34/70 .pdf suggest up to 3gms per litre when pitching below 12c). So two packs properly re-hydrated seems a good starting point.

Plenty has been said about pitching warm and then dropping to ferment temp. I am on the side of pitching as close to ferment temp as possible, if not a little below.

Soooo I didn't add much to the thread, but I did get to blurt out something useful about M84 if someone searches the site, so no harm done. :huh:


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## penrithbeerclub (19/7/13)

Lecterfan,

Sorry, could you explain 1gm per liter? you mean 1 grm of yeast per litre of water?

can I open and add another pack of yeast?

Also I did not re hydrate it, it went in dry.


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## Judanero (20/7/13)

penrithbeerclub said:


> Sorry, could you explain 1gm per liter? you mean 1 grm of yeast per litre of water?


Yes, 1g of yeast per litre.

And you can open it up and tip in another packet, though it is not ideal, you can.


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## Lecterfan (20/7/13)

Yep, 1gm per litre of wort that you are innoculating. This late in the game it might not do much good adding the same yeast again, but this is another topic/issue/debate that I don't know anything about so shouldn't comment.


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## penrithbeerclub (20/7/13)

Thanks, Ill let this one go, how abour rousing the yeast after it slows down or stalls again? any comments?


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## Lecterfan (21/7/13)

Certainly a gentle rousing (sounds lovely ooh err) - avoid aeration/excess splashing etc - and raising the temperature might help. If you are within coo-ee of your FG and want to add more yeast then you will need to select a strain that is a high attenuator and alcohol resistant...it may still contribute some flavour character to the beer, but (hopefully) bugger all compared to the first 72 or so hours of fermentation. You will want to rehydrate the yeast before pitching as per the manufacturers specifications. According to White and Zainasheff you can kill up to %50 of the yeast by sprinkling directly into the wort. Although plenty of great beers have been made from sprinkling a single pack of dried yeast into wort haha. Good luck with whichever way you go!


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## penrithbeerclub (21/7/13)

Thanks, I will def try re hydrating all my yeasts from now on.

However if using the yeast that comes with a kit, how do we know how to re hydrate?


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