fly sparging / raising MT temperature to hold sugar profile

[Brownster]

Hi All, I've just finished another AG this week (Theakstons old peculiar from the GW book, damn I can't wait to try it....) and whilst fly sparging I was trying to get the grain bed temperature up to the 75c mark. As I have only one boiler, my method is to heat the water to about 85c then transfer to a HLT, of course all the time the temp. is dropping, probably about 75c when I start the sparge, then all the time I'm sparging the temp. is dropping further, the result is using my digital thermometer probe I never really got the MT temperature any higher than the high 60's; I'm jugging in the HL into the mash tun and keeping the level over the grain bed and I'm hitting my volume and target OG so no worries there but I'm concerned about changing the sugar profile of the beer.
Am I right in thinking that because I have not raised the temp. in the MT sufficiently to arrest the enzyme action, more sugars are becoming fermentables and therefore changing the profile, or, is it the case that after a 90 minute mash, all if not nearly all the enzyme action is over anyway and therefore the sugar profile is not going to change so it's not really an issue?
If it does matter and I should try to get the MT temperature up more, I'd be interested to know how you go about it with a single boiler set up please?

[vacant]

You could fit a kettle element to the HLT or you could keep the water in the boiler and collect wort in the HLT. The latter means adding around 25 minutes to the brew day as you can't start the boil as soon as the element is covered. Simplest to jug the wort into the boiler when the sparge has completed. I found a plastic 3 litre jug in a DIY store, before that I'd been using a 3 litre plastic milk carton with the top corner cut off (but it was very bendy when hot )

[Dennis King]

for a while when I didn`t have a HLT I used hold back some of the treated water and boil it in a kettle adding to the bulk of the water as it when`t down. 3-4 kettles full would keep the temperature constant over the sparge period.

[Dr. Dextrin]

I start by heating all my sparge water in the boiler to a bit above 80C and then transfer it all to a FV. I then put some of it in a big pot on the stove over a low heat to keep it at 80C. I sparge from that and collect the wort in the boiler.

Since the pot on the stove won't hold all the sparge water, I pause half way through sparging to top it up with the remainder of the water I heated earlier and to bring it back up to 80C (it has generally cooled a bit by now). While this is going on, I just close the outlet tap of the mash tun to suspend the sparge with the grains covered with water.

I haven't noticed any adverse effect from suspending the sparge for a bit and when I measured the grain temperature on my last brew it was sitting nicely at 75C at that point.

[boingy]

Best way is to use the boiler as the HLT and collect the wort in another container. You can use the FV for this if you do not have another suitable container.

Once the sparge is done, transfer the wort from the FV into the HLT (or Boiler as it is now!) and get the boil on. You lose a bit of time like this because the wort cools a bit and you cannot start the boil until the end of the sparge but that's how I did it for years and it was fine. You have plenty of time when the boil is going to clean and sanitise the FV.

Also, don't worry too much about the temperature of the sparge water. There is an ideal temperature for the water but you can get away with quite a variation without the beer suffering. It all depends how purist you wish to be!

[grmills]

Also, don't worry too much about the temperature of the sparge water. There is an ideal temperature for the water but you can get away with quite a variation without the beer suffering. It all depends how purist you wish to be!

Agree sparge temperature is not critical but would suggest that too cool is less of an issue than too hot. I sparged with water that was too hot once and pulled out some less than pleasant tannin-like stewed tea flavours.

On the other hand sparging too cool effectively extends the mash-time and results in a dryer beer than would otherwise be the case. I should think It can be worked around by starting the sparge early, say after 60 minutes (but worth checking for starch with iodine first; I never detect any starch at 60mins).

[Brownster]

Excellent, thanks to all for your advice, looks like a have a number of options there and it's good to know what others are doing. I'm planning another brew as soon as I get the TOP bottled so I can try again with a new technique