another stuck brew question

[johnluc]

Hi all, have been all grain brewing for about 4 years, never had much of a problem, now my last 7 or 8 brews have all stuck at between 1020 - 1016, always use S-04 or S-05 never re hydrated until my first couple of stuck brews, never made a difference, dry pitched or rehydrated all stick, tried all the things, good stir, re pitch more yeast don't work. not my hydrometer as i have two, not a fermenting temp issue as i have a brew fridge, the only two things that coincided with this happening is my good digital thermometer broke and replaced with a new cheap one from china which is very erratic, and i changed my grain from Fawcetts to Crisp MO, I brew pale ales and bitter, hope someone can shed some light on this as it's really p*****g me off now and taking a lot of the enjoyment out of it.
johnluc.

[CestrIan]

I think you answered your own question. Buy another thermometer to cross check the mash temp. If you are mashing high then you may be producing a lot of dextrins that the yeast are struggling to ferment. If you are mashing low then you may not be converting all the starch to glucose.

I use crisp MO and it is top notch. It's not that. Double check your mash temp.

[50quidsoundboy]

+1, i'm amazed by how much mash temps and mashout (or omission thereof) affects attenuation

[johnluc]

thanks for your replies guys, i had suspected it was mash temp, sometimes you need someone else to confirm your thoughts, have got a new eti thermometer on the way.
johnluc.