fundamental basics.

[Ben711200]

Hi,

I'm struggling to get my head around something. You mash at a certain temperature to make the enzymes convert the starch into different sugars with varying fermentability. I get that on the most basic of levels.

What I don't get, is how after mashing for an hour/90 mins at 66, you then have to heat it up to get it to the boil. In between being at 66 and 100, it's also all the other temperatures. Is it a case that the enzymes are there at the different temps, but the starches can only be 'converted' once and won't change?

Have I just answered my own question and looked like a pillock?

[Nofolkandchance]

Simply put, Hop isomerization, sanitation, hot break, etc. GOOGLE it

[orlando]

You're right that once the enzymes have converted the starches to sugar they are "done. Alpha amylase and beta amylase convert over slightly different but overlapping ranges. Mashing slightly higher or lower within those ranges will favour one over the other which is what gives brewers control over the fermentability of the wort and the resulting beer. The point of raising temperature during the sparge is to "fix" the sugar profile you are after as a rapid heat rise will quickly denature the enzymes. Boiling of course is for other reasons.

[seymour]

Good question. I think you've almost got it, and looks like the guys have beat me to the main points.

I think the main reason to heat it up at the very last, is simply for a freer-flowing sparge. You want to rinse every bit of fermentable sugar from the grainbed, and that's done most efficiently at hotter temperatures.

Yes, as you say, you'll be rising through the alternative mash temperatures, but nearly all your useful conversion is complete after 90 minutes, and you won't be stopping anywhere long enough to consider it a separate conversion rest.

Raising the temperature of the wort this way brings the kettle to a boil faster too, which is also handy.

[Martin G]

I like this type of thread, good to challenge why things are done the way they are, now and then it leads to something new.

[gregorach]

Alpha amylase breaks starches down into big chunks. Beta amylase breaks starches or the big chunks produced by alpha amylase down into smaller chunks. Both of these processes take time, and occur at different rates, depending on temperature and pH. After a 90 minute mash, alpha amylase should be pretty much done - there won't be that many long chains it can work on left. Beta amylase will still be working to break the sugars down into smaller, more fermentable chunks. However, beta amylase prefers to work at lower temperatures, so if you do a mash-out, or sparge at a higher temperature, that will reduce its activity significantly. Once you get over about 80 degrees, the enzymes will be denatured and stop working entirely.

[Rick_UK]

However, beta amylase prefers to work at lower temperatures, so if you do a mash-out, or sparge at a higher temperature, that will reduce its activity significantly. Once you get over about 80 degrees, the enzymes will be denatured and stop working entirely.

Thanks for the explanation Dunc. Does this basically mean sparging above 80 will give a less fermentable wort / higher FG?

[orlando]

However, beta amylase prefers to work at lower temperatures, so if you do a mash-out, or sparge at a higher temperature, that will reduce its activity significantly. Once you get over about 80 degrees, the enzymes will be denatured and stop working entirely.

Thanks for the explanation Dunc. Does this basically mean sparging above 80 will give a less fermentable wort / higher FG?

Sparging above 80 stops everything pretty much, but remember by then you have most if not all of the conversion done. What determines the fermentability is what temps you mash at. The lower end will give you a more fermentable wort

[gregorach]

Well, sparging above 80 isn't hugely recommended, as that starts to get into the territory where you risk extracting undesirables - although there can be a big difference between the temperature of the sparge liquor and the temperature of the grain bed or the run off... Really, unless you're doing absurdly long sparges, it shouldn't really make much difference - once you get much above 70 degrees the enzyme activity is very low, so although they are theoretically still active, they're not actually doing much.

I do a mash out to raise my grain bed temp to 72 degrees before I start sparging, and consider that to be the end of meaningful conversion. It might get more complicated if your lengths are counted in multiple hectolitres or your sparge time is measured in hours.

[beer today]

Thats good to know dunc. My last brew the mash out was at 72 and i was worried it was too low according to the text book. However i feel that if the mash has been constant 68 for 60mins then all should really be achieved and the mash out temp of 72 is adequate, hopefully.

[Rick_UK]

Thanks for the explanation chaps. I knew mash temps were obviously the key factor in enzyme balance and thus fermentability never considered sparge temp too much - but usually heat sparge water to about 80 - 85. I have had a few brews finish on the high side hence my question.

Rick

[orlando]

Thanks for the explanation chaps. I knew mash temps were obviously the key factor in enzyme balance and thus fermentability never considered sparge temp too much - but usually heat sparge water to about 80 - 85. I have had a few brews finish on the high side hence my question.

Rick

Temperature is important ,pH more so. Heating the sparge water to 80 even to 85 will end up in the mash tun at a lot less than that once mixed with the mash water that has cooled to sub 65. If you are fly sparging then the heat drop is likely to be more as the liquor is cooling in the drop from the spinning arm, batch sparging probably needs a little more caution with the higher temps. The most important aspect is the mash pH, as long as this stays below 6 then tannin extraction is supposed to be much more unlikely.

[Ben711200]

Thank you all, Dunc especially. That's filled the gaps and answered my question perfectly.

[molehill]

As a newbie to brewing and having just completed what I hope is a good brew #5 today, I moved over to batch sparging on brew #3 topping up each batch at 83c-85c leaving each and leaving to soak for a 20 minutes. Today, I decided to cut each of the soaking back to 10 mins and wondered whether this was a good move or not? As a newbie, I haven't worked out all the technical approaches to getting a flavour that suits me. I read and downloaded this method but am a little concerned that the high sparging temps will affect final flavour?

Method used on Brew #5 which was a Courage Directors G.W recipe. I adjusted my water with CRS, doughed in at 72c, closing lid at 66c, 90 mins later, finished at 65c. Topped up 1st sparge at 83c-85c, left to soak for 10 mins, let runnings clear and ran off, placed into and started boiler. Added required amount for 2nd sparge at 83c-85c and let soak of 10 mins. Then completed the remaining processes according to plan.