Steep at too high temprature

Im brewing a clone of a Samuel Smith Oatmeal Stout. (partial mash)

First question:
I was suppose to steap my grain for 20 minutes at 150, but i didnt manage to have a good control of the heat ant did it mostly at 160...

I know I'm not extracting the same sugar, but what will be the difference on the taste ?

Second question:
I was suppose to get an original gravity of 1.050 but ended up at 1.060. I used Wyeast's 1084 Irish Ales yeast. I had a temprature of 22-23 and fermentation sarted after only 3 hours. After 15 hours it was creazy and I had about 3.5 of head. But after 24 hours nothing more. I have a gravety of 1.010 after a week.

Why so much activation from the yeast so quickly and then nothing more. Its been 7 days today and I I juts transfer to my secondary.

Self bump. Anyone can help with this?

Steeping at 160 is fine, although it's a bit warm. It's not warm enough to denature the enzymes or to cause any tannin extraction, though. so that's fine.

The reason it fermented out in one day is just because it was too warm. Yeast LOVE warmer temperatures but normally the higher temperature can cause some flavor issues.

Here's the info on your yeast strain (from Wyeast's website):
YEAST STRAIN: 1084 | Irish Ale™


This versatile yeast ferments extremely well in dark worts. It is a good choice for most high gravity beers. Beers fermented in the lower temperature range produce a dry, crisp profile with subtle fruitiness. Fruit and complex esters will increase when fermentation temperatures are above 64°F (18°C).

Origin:
Flocculation: Medium
Attenuation: 71-75%
Temperature Range: 62-72F, 16-22C
Alcohol Tolerance: 12% ABV

Since you fermented quite a bit above 18C, you may have some fruity flavors due to that.

Also, keep in mind that fermentation itself produces heat, so in a warm room the actual beer temperature can be as much as 10 degrees higher than room temperature!

For next time, add the yeast to the wort when the wort is about 65 degrees (18C) and don't let it get above 21C for most yeast strains.

S.S. oatmeal stout PM recipe would be a great one for my book.....willing to share?

You did not ask about this but I would like to tell you anyway as you will probably question this later. The reason you F.G. was higher that expected is due to the increase mash temp(steep) temp. It pulled more sugar. As for the fermentation, this is what I do. I take a tub and fill it with water and let that rest until the temperature is equal to the ambient temp. Then I fill up the container I will ferment in with water and set that in the tub... let those two come to and equilibrium. Now you can adjust the ambient temp to be near what you need it to be, around 65 because the added temp from fermentation will heat it up a bit. One thing that people do to it is cut a hole in the lid you get with the tub to fit the fermenter. This will help regulate the temp! Hope this helps.

Thanks for your reply. Its a bit weird since on the label of my yest it was mentioned that I should be used at a temperature of 20 to24 C.

Anyway, I will give it a taste in about 3 weeks and tell you if its good

cheers!