Low SG

[Portreath]

I experimented with a high mash temp (77c )AG brew last night and it came out about 5 points lower than aiming for. So I now have a brew with an SG of 1.029 inserted of 1.034. I'm thinking of adding 200ml of brown sugar syrup but I can't find a calculator to check that this will get me to the target gravity. As anyone got any advice on this?

Thanks

 

[Bigcol49]

Hi!
77°C is very high - that's mash out temperature; it stops all enzyme production. It could explain your low SG.
Sugar: 1 lb in 1 gallon (US, I assume, as I found the info on a US site) gives a SG of 1.045.
This works out at 26 g per litre.
You only want to raise the gravity by 5 points, so add 3 g per litre.

 

[Portreath]

Yes @Bigcol49 very high indeed. I normally mash at 66-67, but having read a few conflicting articles I thought I try myself and see what happens when you mash at 10 degrees higher. Result is low gravity.
Thanks for the formula, I'll let you know how it turns out.

 

[chthon]

No problem with mashing high, but the highest temperature you should use is 70° C. This is the optimum for alfa-amylase, which converts starches into dextrins and other sugars.

 

[NIGHTSKY BREWING]

Top end mash is 71/72 degrees....but 69/70 is the highest for me so far....

 

[chthon]

I always use this diagram as a reference.

 

[ChrisRedWills]

what was temperature when u took the reading

 

[Cwrw666]

I always mash at 146F - 63C. Can't really see from the diagram whether that's a bad thing or not but the beer always turns out fine.

 

[Duxuk]

I like to overnight mash. The long time period causes some of the long chain unfermentables to break down into fermentables. I have gradually increased my strike temperature and am now trialing 71C. With a full volume, minus 6l for mini sparge, volume of water the grain only cools the mash by about 1 degree. I think if I did the same with a 90 minute mash I'd end up with something far too sweet.

 

[Hoppyland]

Just a thought.... Why brown sugar syrup and not table sugar? Off the top of my head, I'd have thought that table sugar would serve to increase the OG without much affecting the malt flavour profile, whereas brown sugar might add its own tang and therefore deviate a bit from the beer you intended to make.

 

[Portreath]

Brown sugar syrup is just a chefy term for dissolved brown sugar. I use brown in most of my recipes, demerara was used in this recipe as I like that little toffee back note it brings.

 

[Portreath]

I plan on doing the same brew this weekend aiming for 67c mash temp and I will try to hold the temp for 2 hours to see what difference there will be.

 

[rank_frank]

when I make low alcohol beers, I mash at 72C to give a lot of flavour from the small amount of malt in use. I know of a local commercial brewery that does that same thing but uses invert sugar to produce the alcohol. Or at least that's what they told me on the tour and why I tried 72C

 

[Portreath]

That's a good point @rank_frank as I don't really brew anything over 5.8% preferring lighter and session ales.

 

[Hoppyland]

I mash at 72C to give a lot of flavour from the small amount of malt in use.

I've never mashed at anything like this temperature. Doesn't it result in a large amount of residual low-fermentable sugars? I would have thought that this would produce a heavy, semi-sweet, almost cloying mouthfeel, rather than a malty taste? I guess you don't find this to be the case.

 

[rank_frank]

Yes it does give a large amount of unfermentables but in the low alcohol beer these are very dilute. It's a while since I did it but I aim for an OG of 1.025, FG of 1.010, using 2-2.2Kg of malt collecting only the first runnings and then diluting to desired pre-boil volume. I make 20 litres at a time. The technique works well for stout and IPA where there's taste from roasted malts or hops but produces insipid bitters.

It's easy to get this wrong with too much of the unfermentables. A commercial example of this in my opinion is St Peter's Without Original. It's got a nasty twang of these long chain sugars.