Partial mash w/ low OG question.

[Dead Money Duke]

I'm trying to move from extract to partial mash. I have a 3 kettle setup, so maybe I'm making a mistake of trying to do a partial mash in a mash tun instead of a single kettle. Anyway, I made an IPA today that came in far too low: 1.036. Target was 1.05. I believe I used too much mash water? I mashed at 153F for 45 minutes, but I couldn't get my wort pump moving with the recommended water for 3 lbs of grain. So, I had to increase the mash water which resulted in a soupy mash. The rest of the process went fine and I added 6 lbs of liquid extract to the boil. My yield was a bit over target, so I probably also sparged in too much water. I mean, I hit the calculated goal of 7G pre boil, but that may have been too high and my problem is my equipment profile in brewfather.

One problem I did not have was temperature control. The mash stayed within 2F of the HLT the entire time.

Am I doing it wrong by trying to do a partial mash + sparge, when I should just do the partial mash in the boil kettle like a steep? I will likely do this recipe again and try that method and then that will help me isolate which part of the process I'm messing up. Alternatively, I could try an all grain version of the recipe and then I'd have a larger grain bill, larger resulting mash water requirement, and less of a problem getting the mash water to circulate.

My question is: what's a good process for working through this error and isolating where things might've gone wrong?

At this point I'm brewing more than I can possibly drink, just to try and improve my process...

 

[balrog]

I'd say first off you need to calculate the water to use and not alter that volume on the fly. And if you're saying things like "I think the volume was" then you need to adjust your thinking just a little -- you need to measure things like temp, volume, SG or you will not be able to successfully recreate and repeat a recipe.

If you add more water to a mash, you then have to recalculate how long to boil off that additional water during the boil that was calculated to boil off only the first amount of water. It kinda seems to me that if you needed more mash water to make it fluid enough to pump, then simple take the amount you added, MEASURED, and remove that MEASURED amount from any sparge you were going to do.

I myself prefer to mash with a BIAB process, in the boil kettle, no sparge.
WHen I used to partial mash, I would still use a bag, and do a "pour over" sparge. But it was partial boil and the only crucial volume was at the very end of everything when I needed to add top up water to make 5 gallons in the fermenter.

 

[Dead Money Duke]

I think part of the problem is also how I used brewfather. The "pre-boil volume" is total water into the system. But that's what I put in the boil kettle. This means my "mash-tun loss" wasn't properly accounted for. I should subtract any pre-BK loss from the amount I expect to see at the boil.

I will do a run without any ingredients - just water - and measure the loss at each step. That will help me plug in the right values and adjust recipes.

 

[CascadesBrewer]

A few thoughts...

What does your system look like? Do it have the capacity for an all-grain batch? If so, and you are interested in all-grain, then maybe you should move toward all-grain brewing. Just keep some DME on hand to adjust if needed. I tend to think that partial mashing is a better fit for people that do not have the capacity to do full volume boils.

What did the grain for your partial mash look like? There is a lot of confusion about partial mashing and steeping. There are a number of factors that come into play with mashing, but it is important that you have enough malted grains to provide enzymes for conversion.

How much volume did you have going into the fermenter? 6 lbs of LME with a 5 gallon batch should get around 1.043.

 

[doug293cz]

I think part of the problem is also how I used brewfather. The "pre-boil volume" is total water into the system. But that's what I put in the boil kettle. This means my "mash-tun loss" wasn't properly accounted for. I should subtract any pre-BK loss from the amount I expect to see at the boil.

I will do a run without any ingredients - just water - and measure the loss at each step. That will help me plug in the right values and adjust recipes.

"Pre-boil volume" is the volume of wort in the kettle at the start of boil. It is less than the total water into the system (strike volume plus sparge volume) because the grain absorbs some of the water, so it never makes it into the boil kettle.

Brew on

 

[Bobby_M]

It seems like you have a 3 vessel HERMS system. There are just too many moving parts in a system like that, and places where liquid goes other than the mash tun, to accommodate only 3 pounds of grain. This is a situation of poop or get off the pot. If you keep using 3 vessels, just do an all grain batch. If you want to continue partial mashing, yes you can just do that in a bag in the boil kettle.

 

[SouthForkBrew]

Was a base malt included in your grains? If not then the specialty grains you steeped would not have added much, if any, fermentable sugars. I've found that some brewing calculators assume that there are enzymes present even when there really isn't, and they add in the gravity points of the specialty grains to the expected pre-boil gravity. That's just one thing I thought about that no one had mentioned yet, but its far more likely that your volumes were just miscalculated as stated above.

I wouldn't personally go through the trouble (because let's face it, you're still going to have beer either way) but you could do a mini boil of concentrated extract with hops and add that to the fermenter. I'd have to do the math, but I'm thinking if you made a gallon of 1.070 wort and added that in it would get you closer to the gravity you were looking for. Again, that's a lot of work and the hop profile would be near impossible to predict, but technically you could do it.

Cheers!

(EDIT: Just realized someone mentioned the whole partial mash to steeping issue above. My bad...lol!)

 

[IslandLizard]

Good points were already given, above.^
3 vessel systems are meant for all grain, not really for partial mash.
BTW, how big (volume) are those 3 vessels?

I guess you're recirculating the mash. Fly sparging? Is there a false bottom in the mash tun? How large (volume) is the dead space underneath the false bottom? All those factors, and a bunch more play a role in the efficiency of and losses in your brew system.