I ran a little experiment today to see how long mash conversion takes. This has been discussed many, many times on other threads so I thought I'd do my own experiment and post the results.
9.5lbs of grain -- Thin mash 2qt/lb -- 60min total -- Strike water @162F to reach a starting mash temp of 151F -- I took gravity readings using a refractometer
Minutes ------- Gravity
2.5 --- 1.036
5 --- 1.040
10 --- 1.043
15 --- 1.049
20 --- 1.052
25 --- 1.054
30 --- 1.057
45 --- 1.063 (possible bad stir?)
60 --- 1.061
* Lost 5-8F over hour due to stirring every 5-15min
Sparge: 3.5gal @ 195F to reach 168F
0 --- 1.016
10 --- 1.019
Combined Runnings: 7.5 gal
1.040
So, I had an odd reading at 45min that then decreased at 60min. I have to assume I didn't give a good enough stir at 45min. My overall findings here are pretty clear though. Full conversion may have been done as early as 45min possibly even a bit earlier, but gravity was still rising after 30min.
I do plan on running this same experiment again but with a barley wine where I'll be using a much thicker mash of around 1.25qt/lb. Hoping to brew that beer and have results in either 2 or 3 weeks.
9.5lbs of grain -- Thin mash 2qt/lb -- 60min total -- Strike water @162F to reach a starting mash temp of 151F -- I took gravity readings using a refractometer
Minutes ------- Gravity
2.5 --- 1.036
5 --- 1.040
10 --- 1.043
15 --- 1.049
20 --- 1.052
25 --- 1.054
30 --- 1.057
45 --- 1.063 (possible bad stir?)
60 --- 1.061
* Lost 5-8F over hour due to stirring every 5-15min
Sparge: 3.5gal @ 195F to reach 168F
0 --- 1.016
10 --- 1.019
Combined Runnings: 7.5 gal
1.040
So, I had an odd reading at 45min that then decreased at 60min. I have to assume I didn't give a good enough stir at 45min. My overall findings here are pretty clear though. Full conversion may have been done as early as 45min possibly even a bit earlier, but gravity was still rising after 30min.
I do plan on running this same experiment again but with a barley wine where I'll be using a much thicker mash of around 1.25qt/lb. Hoping to brew that beer and have results in either 2 or 3 weeks.