Fly Sparging temperature

[JammyBStard]

Bit of expert help please, I'm Mid mash at the moment!

After Mashing at 67'C I'm fly sparging using water at 76'C.
However the temperature of my grain bed has dropped to about 59'C

Is this ok, or should I be maintaining a graing bed teperature of 67'C as per the mash?

[edit1now]

I mash-out at 78°C by raising the HERMS temp - not possible for everyone - and then fly-sparge with water at 85°C (measured with the PID probe in the sparging tee). This seems to keep the mash at about 76 - 77°C, which is about the optimum temp for sugar solubility. The sparge liquor cools as it drips onto the mash bed...

[JammyBStard]

Thanks E1N
If 76 - 77°C, is the optimum temp for sugar solubility, why do we mash at 67' - 68' C?

[edit1now]

We mash at 66 - 68°C because that's the optimum temp for the malt enzymes to eat the starch in the grains and convert it into sugar for the yeast to eat. A higher temp (69 - 70°C) will give more body (unfermentable sugars) but less alcohol, and a lower temp (60 - 64°C) will give more fermentable sugars and less body in the finished beer.

[JammyBStard]

of course, silly question sorry

[rick_huggins]

FWIW I fly sparge at around 85

[JammyBStard]

Cheers all, I was fly sparging at 76, but this time i raised the temp to 85 halfway through and got a noticible increase in OG!