Mash Temp/Fly Sparge Question

[Brewtus_Maximus]

So yesterday I was brewing up an IPA. After my conversion was done, I raised the temp of the mash to 168 F by heating it on propane while stirring. Once I was to mash out temp, I did my vorlauf, which reduced the temp a little bit.. Then I started to fly sparge with water that was ~ 180 F. Surprisingly my mash temp dropped even more and went down to around 155-160 F while fly sparging (took about 50 mins in total to sparge) in spite of the warmer sparge water.

I still got decent efficiency (77%), but I am assuming that it is important to keep your mash at about 168 F while fly sparging. I've heard that some people don't even do a mash out, and that as long as the sparge water is at the right temp, you should be good to go. So this brings me to my question: how important is it to keep your mash temp at 168 F while fly sparging? It doesn't seem that not doing so had much of an effect on my efficiency, but I am curious if it will have effects on flavor.

I think my biggest mistake was cutting off the flame on the mash tun when I reached mash out temp.. I should have kept the flame on when I was vorlaufing. I was afraid of getting scorched grain on the bottom, which is why I only kept the flame on when I was stiring the mash. But I think I may have been a bit too paranoid. My mash tun has a triple-ply bottom and I didn't notice any scorching of the grain at all (I used a bazooka screen and not a false bottom).

Any advice on how to keep mash temps stable during fly sparge without recirculation pumps will be much appreciated.

 

[RM-MN]

When you are fly sparging you tend to keep the temperature at or near mash temperature. To keep the grains from continuing to convert, you mash out at ~170 for 10 minutes because that is what it takes to denature the enzymes to stop the conversion. From that point on, there are no enzymes active so you can sparge at any temperature. Most people want to sparge between 150 and 170 because the sugars will readily dissolve into the water you add but by keeping the grains under 170 you minimize the tannin extraction.

 

[DurtyChemist]

I believe the mash out is only to destroy the enzymes that are active during the mash. Even if the temperature drops, your only rinsing the sugar from the grains not converting anything. Mash out destroyed the enzymes.

 

[helibrewer]

I don't think keeping the temp up high has a big impact on our 50-60 minute sparges. For brewery size batches that whirlpool and lauter for several hours I can see it, but we have about all the conversion we are going to get after 1 hour in the MLT, another 50 minutes in the 145-160 range isn't going to change much if anything.

 

[BadWolfBrewing]

I see a sizable hit in efficiency if I don't mash out. I had attributed it to the sugars dissolving more readily when warmer

 

[Brewtus_Maximus]

Thanks for the replies everyone!

I was thinking that my lower sparge temp probably didn't affect it that much as my efficiency was still decent.. From what ya'll are saying it sounds like a grain bed temp of 150-160F should be just fine while fly sparging. My mash tun thermometer has a little mark at 170F that says "sparge" (right above the "mash out" mark).. So this is why I was concerned with keeping the temp there during sparging.

It took me about 10 minutes to heat to 168F, and then I started my sparge.. But if I am understanding correctly, once I reach this temp, I should cover the mash tun and let it sit for 10 minutes before starting the sparge, right?