High gravity AG

[azazel1024]

I now have my 3rd batch of AG under my belt and feeling my oats (pardon the half pun). I friggen LOVE AG brewing.

I have two questions/issues though. My one issues is I only have the gear to do up to 3.75G batches, unless I want to go really low gravity or do partial mash...I am fine with that. Smaller batches means I have to brew more often.

Oh darn.

Next up is, how do you go high gravity? At least with my method (using DeathBrewers stove top AG method here https://www.homebrewtalk.com/f39/easy-stovetop-all-grain-brewing-pics-90132/), I am running between 65-72% efficiency, which I am fine with. However, as the gravity goes up, my efficiency goes down.

I am assuming there is a tipping point where I am going to run out of ability to add grain and/or my efficiency just tanks as much as adding grain makes up for it.

My current "high point" is a 1.067OG India Brown Ale that was 68% effiency and a 2.5G batch (About a 3G boil, minus losses to the grains).

However, by my math I don't think I can get much higher than that as it required me to use only around 1.25QT per lb of grain in my first pot IIRC.

By my math, assuming effiency holds steady (and I'd expect it to drop at least a little) I can maybe hit 1.08OG before I am going below 1qt per lb of grain.

So, how do I go to higher gravities for Imperials and Tripples? Do I do longer boil times to boil it down more? So, I'd prep/mash for a 3.75G batch for example (which would mean around 4.25G or so boil size) and then boil it for longer to get down to, say, a 3 or 2.5G batch size instead of a 3.75G batch size?

Just trying to figure out where to go from here to get really high gravity beers. My next couple of moderate gravity beers, but 3 brews out I am planning an Oatmeal Coffee Milk Stout and I'd like to make it Imperial (I am thinking I'll target a 1.085-1.095OG)

 

[LovesIPA]

I don't use the AG method described in that thread, but have you considered using a more conventional all-grain brewing setup with a cooler mash tun? I can brew as big of a beer as I want with my 10 gallon igloo cooler.

 

[solbes]

I have a 7.5 gallon pot and do Brew in a Bag in 5.75 gallon batches. My efficiency varies between 70% for largest brews and 86% for lower gravity brews. Highest OG without adding adjuncts or extract has been 1.066. Some potential ideas:

- Easiest is to add DME or late addition LME. Nothing wrong with partial mash, they taste delicious. I added a lb of DME for a Wee Heavy, 6 lbs of LME for a massive RIS, and plan to add 6 lbs of Maris Otter LME to my Barleywine that's on deck. Dubbels, Triples, and Quad's usually get between 1 and 2.5 lbs of sugar (or candi syrup).

- Crush your grains finer. This will give you more trub however, so use a fine voile bag to catch as much as possible.

- Mash longer and always do a mashout to 170F. This means heating your mash to 170 before sparging. I find I get a more efficient sparge this way, as more of the sugar has been worked into the wort beforehand. You may have issues scorching the bag to the pot, but I use a turkey frier basket. Mashing longer may thin out the body some on low gravity brews, so keep that in mind.

 

[azazel1024]

Thanks for the feedback.

As for a more conventional setup, I don't really have the money or space required for it. I have a 24qt pot and a 12qt pot (which is probably also where I am losing efficiency).

I generally do (for a 2.5G batch) around 10qts and grains in the 24qt pot for around 60 minutes at around 150-155F depending if I am going to a little sweeter or a little drier. I then heat up 4qts of water to about the same in the 12qt pot, drain the mash and plop it in the 12qt pot for 15 minutes and then raise the temperature to around 170F before the final drain and mix it back in to the 24qt pot.

Probably what would help efficiency (and I could brew larger batches) is to have a second 24qt pot to use so that instead of 4qts (6qts for 3.75G batches, but that is filled pretty much to the brim with grain and water in the 12qt pot, depending on the gravity) in the 12qt pot I could do more of an even split between the two pots.

I am also thinking that probably increasing mash out temp to 170F in both pots might help (I am guessing probably all the starches are converted after an hour at 150-155F).