Mashing temperature

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The two main enzymes active during the mash are alpha and beta amylase. Alpha amylase, which is most active in the 154-167F/68-75C range, creates longer sugar chains that are less fermentable, resulting in a beer with more body. Beta amylase, which is most active between 130-150F/54-65 C trims off single maltose sugar units that are more fermentable. This results in a more complete fermentation (higher attenuation) and a cleaner beer with a thinner body.

Most aim for around 67c with maybe a drop of 1c.
 
It is fairly easy to maintain the temp with a large amount of liquid and some insulation.
Some guides show wrapping the boiler in an old blanket or duvet which does the job for me.
The bulk of the process is done within 15 mins so even with heat loss you'll still get acceptable conversion.
 
Just start with your water at 70C. Get the malt in the bag quickly and straight into your insulation. I use a piece of thermal underlay on the ground and a sleeping bag. Tuck it up nice and cosy and DON'T WORRY. I have done 6 brewa in a bag with efficiencies from 77% (first time) to 89.7% I have found that the higher the gravity, the lower the efficiency, as a general rule.
 
I have a question about mash temperature so thought it better to tag onto this thread than start up a new one. I did a BIAB yesterday. It was an Ace of spades porter clone from malt miller. By the time I got it all in and wrapped with a 13.5 tog king size quilt on it the water temperature was still at 69.2 degrees C. Although this was higher than the 65 suggested for this recipe I thought it would drop quite a bit over the 60 minutes as it was pretty chilly outside compared to when I’d done my previous brews. I took everything off half way through to give a good stir and wrapped it up again but had clearly underestimated the efficiency of the insulation and it was still at 67 degrees at the end of the mash. I carried on as normal and on taking a gravity reading just before picking the yeast and with the wort temperature at 21 degrees the SG was at 1.044 whereas the expected SG should have been 1.055. Am I correct to assume the reason for this likely to be because the mash temperature was too high?
 
I have a question about mash temperature so thought it better to tag onto this thread than start up a new one. I did a BIAB yesterday. It was an Ace of spades porter clone from malt miller. By the time I got it all in and wrapped with a 13.5 tog king size quilt on it the water temperature was still at 69.2 degrees C. Although this was higher than the 65 suggested for this recipe I thought it would drop quite a bit over the 60 minutes as it was pretty chilly outside compared to when I’d done my previous brews. I took everything off half way through to give a good stir and wrapped it up again but had clearly underestimated the efficiency of the insulation and it was still at 67 degrees at the end of the mash. I carried on as normal and on taking a gravity reading just before picking the yeast and with the wort temperature at 21 degrees the SG was at 1.044 whereas the expected SG should have been 1.055. Am I correct to assume the reason for this likely to be because the mash temperature was too high?
I don't think the mash temperature would account for 10 gravity points difference in SG. The temperature you mashed at was very normal. Either your system is not as efficient as the recipe expected, in which case you can increase the amount of grain you use. Or, your volumes were off and you needed to boil off more / add less water in the first place.
 
Ok, thanks. There was a typo in the original post, sorry. Expected SG was actually 1.050. Not as bad as I put but still a little down. I must have started with too much water. I ended up with the correct amount of wort but I think that was mainly because there was a good few litres lost to trub (but that’s another matter). So, if I’ve lost 6 points from the SG, does that make any different to the expected FG?
 
markk
biab needs a finely milled grain to get maximum efficiency I found the kits u buy are based on 3 vessel brewing if i buy a kit i always mill the grain again to as fine as I can get the more flour the better a good mill can be your best friend when doing biab happy brewing
 
Ok, thanks. There was a typo in the original post, sorry. Expected SG was actually 1.050. Not as bad as I put but still a little down. I must have started with too much water. I ended up with the correct amount of wort but I think that was mainly because there was a good few litres lost to trub (but that’s another matter). So, if I’ve lost 6 points from the SG, does that make any different to the expected FG?
Expected FG is impacted by the mash temperature and a number of other factors such as amount of yeast pitched and type of yeast used amongst other factors. FG should still be near predicted.
 
How much trub did you have as this does have a bearing on the full volume. If you say had 2 litres Plus you have had too much volume which would affect the OG. I normally lose about 1 litre max to trub etc
 
Oh, there was at least 2 litres left in there I'd say. I suppose if I'd left it to settle for longer I'd have got more out but was worried about infection as I was outdoors.
 
It is where a lot of efficiency is lost if not transferred to the FV if you think that another litre could have possibly been eeked out it does help to get nearer the efficiency. It is all part of improving your process over time and I am sure you will get better figures next time. Too much emphasis on figures can distract you from the process which is to make good beer and as I have said the figures will improve as you perfect a process that works for you.
Ps some brewers tip all the trub ion to the FV and with no seemingly no worse affect as they say it settles out in the fermentation process
 
It is where a lot of efficiency is lost if not transferred to the FV if you think that another litre could have possibly been eeked out it does help to get nearer the efficiency. It is all part of improving your process over time and I am sure you will get better figures next time. Too much emphasis on figures can distract you from the process which is to make good beer and as I have said the figures will improve as you perfect a process that works for you.
Ps some brewers tip all the trub ion to the FV and with no seemingly no worse affect as they say it settles out in the fermentation process
Yes, I'm sure my processes will improve. I make notes of everything so now know how much water to use next time. I'll also not worry as much about not transferring the trub. My FV has the tap with a sediment traps and seems to do a pretty good job of keeping it out of the bottles.
 
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