mashing temp question

[chaos]

hi - Ive brewed for a long time and mostly all grain but never been fully clear on this issue :

If I begin a malted barley mash at around 68-70 deg and hold it for an hour or so I believe Ive activated the enzymes that produce mostly dextrin's (ie. long chain sugars , less fermentable sugars) ../ correct ?

Alternatively mashing at the 60 deg mark or thereabouts tends to produce more maltose - shorter chain more fermentable sugars..?right?

two things - if the temp is held in 70 deg range for an hour or so then is moved down through to 60 ish does the dextrin then get converted to maltose ? or once a dextrin always a dextrin ?

And also, if I'm using the grain to convert other starches eg oats/corn, is it better to convert at the higher temp (?) then step it down to the lower range ? would i get a better conversion -dextrin to glucose this way, or can the grain convert straight from starchy oats to glucose at 60deg..?
thanks

[bluc]

70 is a touch high. 63-65 will give you best conversion and fermentability. Allowing both beta and alpha enzymes to work. Some go as low as 60, other people buy seperate enzymes and mash up in the high 80's. Different temps will change flavour. Experience will tell what works best for you.

[chaos]

OK, thanks Bluc - I take you you are saying that most conversion happens in that range so stick with that.

[bluc]

Yea most people mash in the 60-65c range :handgestures-thumbupleft:

[Garfield]

Bluc is spot in with conversion at mid 60s

Chaos, I suspect your question is really about how to convert a combination of barley and other cereal adjuncts right? Most brewers and distillers do a cereal mash on grains like corn, rice, oats and unmalted wheat/rye. Plenty of content out there on cereal mashing but basically you do a seperate conversion and boil of just the cereal (with 10% barley) and then you add it to a the main barley mash at normal temperature. If you do it well you'll make a very complex and fermentable wash. Mashout if you want but generally that's just for brewers, there's an advantage to keeping the enzymes in the fermenter

To answer your literal question - mashing low to high builds maltose, beta glucans and dextrins. Mashing high to low won't achieve this as the necessary enzymes are temperature sensitive and won't replenish once denatured by a higher temp. That's assuming you don't add enzymes

[chaos]

OK thanks Garfield - your last point answers my question..high to low will not get me where I want to go.. :D