Temps too high in these mash instructions?

[Longbeer]

I'm following a recipe for Stone Smoked Porter clone. The recipe is from the Stone book, so you'd think it'd be spot on. But the mash temps seem high:

Mashing

In a 10-gallon insulated cooler, combine the crushed malts with 3 gallons plus 13 cups of 173°F water. The water should cool slightly when mixed with the grain. Hold the mash at 157°F for 10 minutes.


Add 2 gallons plus 2 cups of 182°F water. The mixture should come up to 165°F.

This looks like an alpha-only mash. I'm very new to mashing but 10 minutes seems short and 165 seems dangerously hot. I've cross referenced this with all other clone recipes for this beer which just suggest an infusion mash at 153-154.

If I follow the above instructions will I end up with little to no fermentable sugars or can I expect to get enough fermentables to make a decent beer?

Thanks in advance!

 

[tv187u]

The mash conversion is close to +-80% complete that quickly, the last +-20% takes a bit more time. Typically a home brewer can wait the longer time and get much better efficacy. A brewery is going to have great efficacy and time is money so they are ok with getting lower conversion rate and turn the mash out after a short time.

The 165*f is for a mash out that stops the conversion. 165-170 is typical.

 

[diS]

Beta-amylase is temperature unstable and it starts to deactivate at temperatures higher than 149F while alpha is more stable at those higher temperatures, so you'll end with a lot of unfermentable sugars with this mash.

Depending on what you want to achieve you can make a different mash schedule, it is all up to you.

 

[Hammy71]

The mash conversion is close to +-80% complete that quickly, the last +-20% takes a bit more time. Typically a home brewer can wait the longer time and get much better efficacy. A brewery is going to have great efficacy and time is money so they are ok with getting lower conversion rate and turn the mash out after a short time.

The 165*f is for a mash out that stops the conversion. 165-170 is typical.

Yep, proffesional brewers can usually get away with a much shorter mash time. It's a porter, so 157F doesn't sound too bad. You want some body. And like tv187u said, 165F is the mash out temperature to stop conversion.

If it was me I would mash at 157F for 60 minutes and then I would sparge using hot enough water to raise my grain bed temperature in the mid 160s. (Assuming your batch sparging.)

 

[bierandbikes]

Agree on the 157F for 60 minutes. I did a smoked porter of my own design and mashed at 156 for 60 minutes, then mash out, batch sparge. It was an awesome beer with good body. I like to do a higher mash temp for porters and stouts to give them that extra body that you expect with those flavors and color.

 

[Longbeer]

Thanks all for the replies! The recipes in that book have been scaled for homebrew and most of them call for 45 to 60 minute mashes. So I was curious why the porter was so short. maybe it was to not over-extract too much smoke from the peat smoked malt.

I ended up mashing at 157 for about 12-13 minutes and then mashing out. But I didn't have my sparge water ready so the mash sat there for another 30 minutes while the water heated. I got a nice delicious looking wort out of it and after boil the OG was 1.062. Lots of fermentation activity. I'm going to declare success, and if for some reason I didn't get enough fermentables then I'll just call it... um... a dessert porter.