Yeast Attenuation

[Crusader-Rob]

Interesting notes regarding some of my recent attenuation. I'm unsure of reasoning, it could be incorrect mash temps or poor yeast health.

Recently: 

Patersbier: 1.045-1.014, mash temp 67deg C, 73% apparant (WLP530)

Scottish Ale: 1.057 - 1.024, mash temp 68, 58% Apparant (M/Jacks Burton Union)

American Pale Ale: 1.055 - 1.014, Mash Temp 66, 76% apparant (US-05)

The american Ale, doesn't really count as its 76%, which is not too bad. was a pretty tasty beer too.

the other ones are the issues I have. I'm tying to figure out why I'm not getting the attenuation recommended by the yeast. (WLP530 is 75-80%)

and my Scottish beer was up to 70-75%.

how can I improve my Attenuation?

[Ralph]

My 2 x results with M79 - Burton Union (which they say should be 66 - 70%). Both brews have been about 1.040 and finishing about 1.012. Both times it was dry yeast packets, rehydrated in water and pitched. Both lots were bought from Finney's.

Current brew - 68%

Previous brew - 71%

Both were mashed about 67 - 68 deg. The recipes were slightly different. Probably a bit more specialty malt in the current brew.

Temperature - Pitched at 19 deg. At least 24 hour lag phase. Once in high krausen/active phase I raised the temp by 1 deg to 20. As airlock activity slows I raise the temp to 21. Leave the beer in the fermentor a few days after airlock activity has stopped to clean itself up. This will be at 21 deg. I ferment in an old fridge - with a 40W element in the bottom... which warms the air to warm the fermentor. These brews were both 50L batches which is a bit more thermal mass... so the warming of the brew by the air is probably reasonably gentle on the yeast.

You dont happen to have the fermentor sitting directly on the heat pad? Direct heat might upset the yeast a bit?

Almost everything else I have brewed lately has been over 70% and some are over 80%... apart from an IPA that I mashed at 70 deg...  1.064 down to 1.026 and the yeast attenuation was 58% - quoted figures for that yeast are 70 to 80% - These are similar figures to your Scottish Ale with a yeast that is supposed to attenuate better... This is the reason we are asking about the thermometer calibration. It could also be where in your mash you are measuring as there tend to be hot and cold spots?

[Crusader-Rob]

Interesting about your experience with Burton Union Brett.
The heat pad pad sit under the fermenter. But in under by maybe 10mm so not directly persay.
Got an epic clone in currently so it'll be interesting to see where I end up with that. Seems a good test for my processes.
Will check the temp of my thermometers soon, probably step 1.
Ralph u think the heat pad could be an issue?

[Crusader-Rob]

I have just check my Mash thermometer, in ice and water, sitting at 0.1 deg C

I'll check the calibration of my fermentation ones tonight to be sure its not that.

I'l start re-hydrating again on my dry yeasts, I've just been lazy. 

I might look at installing a heat lamp of some sort into my fridge to remove that issue if there is one.

when it coms to even temperature, its difficult to make sure of even temperature, I stir alot more vigorously, to make sure its even maybe 5 mins or so.

what are peoples thoughts on 90 mashes?

[Ralph]

As long as the heat pad is not directly against the fermentor it should be ok.

0.1 deg in ice and water is close enough for the cold side. I would try it in a pot of boiling water for the hot side.

If you give the mash a good stir then the initial temperature should be good and I assume the temperature will only drop from this point -  which should lead to a more fermentable mash rather than less.

[Crusader-Rob]

thats not a bad idea, make sure its ok with hot water too.
Yeah generally thats what happens, i normally lost around 2-3 degrees during a 60-90min mash.
If I wanted to change from a heat pad to something else for heat. what should i use?

[Ralph]

old wardrobe heaters, foot warmers or light bulbs work.

I have a 40W light bulb in the bottom of mine... No worries about light and the brew because my fermentor is stainless steel.

[Crusader-Rob]

A what?

[Scarrfie]

I have had some bad runs with some yeasts as well and each time I think back to the early advice I was given by Albrecht, just use one yeast to start with. The idea is to learn to perfect the use of one yeast before branching out to try others. 

So I wonder if you are trying too many yeasts Rob? But guilty has charged also mate. Lol. Best beer I have made is the Irish Stout I have posted about and that was my 10th batch with K-97, or probably the 4th generation. With a dryer yeast just mash high for suitable body. When I went away from that to S-23 I started getting problems again, even bottle bombs for the first time! I had got complacent after a trouble free time with the Altbier yeast. With that one yeast I have done everything from Stouts to pseudo lagers and I am kicking myself I didn't stay with it. Mind you the massive Krausen causes me headaches.

Interesting that Peter (Smith) has given me some of his Youngs and that missed the mark by 3 points. But I gave it a good stir up and it dropped another 4. Expected was 1.019 and I have 1.018, so will bottle tomorrow. Peter was also good enough to give me 3711 and some 1084. 1084 has to wait until I get some more grain, but the 3711 has turned into an 8% Saison because of both overshooting efficiency and attenuation.

[Peter Smith]

I am going to have a go at a fruity blonde with the youngs, this time, so that if it doesnt finsih low it will be no biggie, going to mash way low. 3711 is a beast!!!    my Dupont saison is going great guns as well, thats recoverd from dupont saison bottles not the wyeast one, there is talk the bottles are almost a blend.

[oliver]

Another thing to consider is mash pH which will affect both enzyme activity in the mash and yeast activity in fermentation: http://braukaiser.com/wiki/index.php?title=Effects_of_mash_paramete...

As long as you're within the nominal range you should be fine though.