Bloody Fermentation!

[Ross]

Never had a problem with body mashing at 65c. Add a little munich if you want to lift the maltiness.

cheers Ross

 

[rich_lamb]

As you say, a degree makes a lot of difference - normally I'd expect about that attenuation if I mashed at 69 and used certain strains of english yeast, possibly a tad higher if using US-05. I don't think there's a dud-yeast problem out there; I used US-05 a couple of weeks ago and got excellent attenuation (actually higher than I expected, but I mashed a degree lower than I should have). But without comparing batch codes its a bit subjective.

Hang on, when you say "mash thermometer" you aren't using one of those bimetal dial thingys are you? Those are rubbish for accurate measurement - you can calibrate them to a limited amount, but only at a certain point as you cant adjust both scale and offset.

I'm still betting on the wort as your culprit, ie. your mash temp.

Aside - no offence, but it still gets me that smart people will offload the most creative part of brewing (IMHO, the recipe) to Jamil. Could say "why don't you ask Jamil why it didn't work then". Hold the phone - Jamil told you to mash lower! You picked a fine time to think for yourself

 

[manticle]

Look at hochkurz mashing - mash low for a bit, then high. Best of both worlds.

 

[rich_lamb]

I'm a confirmed yeast rehydrater, but I do agree with MHB's comments - you can easily do damage if you don't pay attention. Could introduce an infection from the additional contact, or if you don't cool the water enough you could kill a good proportion of your yeast (it doesn't take much - Chris White told me that 40 degC would do it, and he didn't hesitate with the answer).

I guess the theory dictates that dired yeast are fully saturated with sterols too, so the aeration should not be necessary for dried yeast.

 

[kieran]

Aside - no offence, but it still gets me that smart people will offload the most creative part of brewing (IMHO, the recipe) to Jamil. Could say "why don't you ask Jamil why it didn't work then". Hold the phone - Jamil told you to mash lower! You picked a fine time to think for yourself

None taken. I usually develop my own recipes, I just wanted to try that recipe because I've had the book for 4 years and never used it and wanted to contrast and compare with my own prior efforts. So perhaps "people" from time to time want to get a "baseline" for calibratiion for their own recipe development.

As for thinking for myself, I clearly wasn't.
5am sunday morning brewing starts sometimes have their hiccups due to early morning mind fog. Even with a plan. The other two times was all me, and in the end I was happy with the result. I do have a bimetal mash tun thermometer, and I think that is going to have to be replaced with something superior.

I do like manticles idea of hochkurz mashing though. Sounds entirely sensible from a scientific perspective.

Thanks for the input, much appreciated.

 

[Synthetase]

If you want to calibrate your thermometer, don't waste your cash on a cheap mercury. Any science supply shop will sell you an alcohol thermometer accurate to within a degree for under ten dollars. I've seen some terrible "cheap" thermometers that cost over that amount (one from one of the sponsors above) reading -8 degrees in an ice-water bath and 110 degrees at the boil.

 

[kieran]

If you want to calibrate your thermometer, don't waste your cash on a cheap mercury. Any science supply shop will sell you an alcohol thermometer accurate to within a degree for under ten dollars. I've seen some terrible "cheap" thermometers that cost over that amount (one from one of the sponsors above) reading -8 degrees in an ice-water bath and 110 degrees at the boil.

I'm a postdoc in a research lab, acquiring a quality regular thermometer is the least of my worries. Albeit having a 1/2" BSP stainless threaded thermometer (bimetal or otherwise) is something we simply dont have here.. Perhaps a thermowell/NTC temp probe combo is the way (maybe with some thermal conductive). I have four now (2x Fridgemate, 2x STC1000) so I should probably put them to use (!!).

We don't have mercury here in the lab (they are strongly discouraged), and I'd never, ever, put one anywhere near foodstuffs or tools handling foodstuffs. I've seen too many break over the years and various 'accidental' and 'inconceivable' events have seen contamination of a larger than expected area. So I just avoid them as par of the course.