Mash temp & FG

[b-radbrew]

So I've been trying to read up and figure this out on my own, but I'm really getting no where other than just confusing myself. I'm basing this off of a porter that I had made recently too that I felt came out a little thinner than what I wanted. I hope I don't confuse anyone with the way this comes out:

If I build a recipe with, just for example, a OG of 1.054 and expected FG of say 1.014. That gives me an abv of 5.25%. Now, thats with a mash temp of 152 for 60 min. So if I wanted to give this beer more body I would mash higher, right? So let's say I mash at 158 for 60 min. From what I understand, I will have more less fermentable sugars at that point, which leaves me with a higher FG correct? So at that point my ABV would then be lower. If i'm on the right track with that, if I still want to be in that 5.25% range, how would I go about tweaking the origianal recipe to account for the loss? Or am I completely off track here?

Does the mash temp really have that much effect on OG and FG or am I making things more difficult than what they really are?

 

[Bowtiebrewery]

OK I see your logic. You could scale up the recipe a bit and add some more Base malt to bump your gracity up a few points so that when it finishes a little higher than what you would have had (if you mash at 158 vs 152). That would work, however I would recommend one other thing, if you are looking for a more full body, see what kinds of malts you could add to it that would help you get there. Toasted malts, melanoidin, Biscuit, Honey... Those will help get you there and not impact your bottom line... I would say this first... Instead of changing mash temp too extreme, try a small compromise on both ends... Go from 152 to 155 or 156 and add in some cara-pils... not too much... maybe .5#. That should give you more body on both ends and most likely not impact your FG too much... You may end up maybe 2-3 points higher. Try that before swinging too much one way.

 

[z-bob]

I'm in about the same place as you; reading anything and everything, and trying to sort it all out in my head first. I don't have the luxury of brewing every weekend and learning from my mistakes. (I wish I could)

I think you're basically got it, but 158° is pushing the limits -- maybe increase the temperature in smaller (2 degree) increments?

Adding a little flaked barley should add both body and alcohol. It wouldn't take much to make up for the higher mash temperature. Try adding 4 to 6 ounces of flaked barley, and mashing at 154° or 155°. That won't change much but should take you in the right direction.

 

[b-radbrew]

I think I was over-thinking all of this. I don't remember the grain bill on the porter but I think I will go ahead and make it again but use your guys' suggestions. I'll add a little cara-pils in there and then go with the couple degrees higher for mash. Thanks

 

[JimRausch]

Another thing you could do is something I do frequently with my german-style brews- a 2-step mash. Start with your 147-152 mash and after 20-30 minutes increase to 157-158. Hold there for another 20-30 minutes. Can do this either by doing a boiling water infusion, or do a decoction(or direct heat if you do BIAB in a kettle). I do believe I get a couple extra points of efficiency as well.
I've read a lot of opinions both ways, but this seems to work for me.

 

[rodwha]

How would this work if done in reverse (starting higher and ending lower)?

My mash tun isn't very efficient and I typically seem to lose 2-3* after 35 mins so I try to shoot for a slightly higher number so that my ending temp isn't too far below 150-2*.

 

[JimRausch]

Going back to J.P.'s simplified explanation in 'How to Brew', alpha-amylase is more active at the higher temperatures, and alpha is the one that tends to leave more longer chain, less fermentable sugar molecules. But the higher temps also tend to denature the beta-amylase which tends to chop off the simple 1 and 2 chain easily fermentable molecules. So, starting high(around 158) and dropping down to 147 or so, wouldn't work as well as starting low and increasing.
But rod- unless you are starting off way high, I think you are probably OK since your temp drops within 35 minutes. If it works for your system, then I wouldn't mess with it too much.

 

[b-radbrew]

Another thing you could do is something I do frequently with my german-style brews- a 2-step mash. Start with your 147-152 mash and after 20-30 minutes increase to 157-158. Hold there for another 20-30 minutes. Can do this either by doing a boiling water infusion, or do a decoction(or direct heat if you do BIAB in a kettle). I do believe I get a couple extra points of efficiency as well.
I've read a lot of opinions both ways, but this seems to work for me.

I BIAB and have been wondering about trying a step mash. I might give it a shot. I think I'll change one thing at a time as I go through this and see how the results come out. I try to keep a pretty good log book going on each batch so I can always go back to what I did before and see what I did. My trial beers are all 1 gallon so it would be easy to gather up the stuff and do a few batches of the same beer all with a different tweak in a relatively short span. Guess I'll start planning a weekend of brewing.

Thanks for the input guys