Troubleshooting: Very inefficient mash - imperial IPA

[bakk]

Hey All,

I just spent the last 45 minutes or so scouring the forums for a thread or two that's similar to my current dilemma with no luck, so here goes.

Tried brewing an AG Imperial/Double IPA today, pretty simple bill:
15 lbs 2-row
1 lb flaked wheat
1 lb c-40
1 lb biscuit
1.5 lbs dextrose (added during boil)
(No Rice Hulls!)

Gear setup is a 10gallon round cooler with a stainless braid false bottom. Batch sparging.

- I was rushing initially, so I poorly estimated water needed for dough-in and heated 3 gallons of water, poured all my grain in, and stirred before realizing it was much too thick. I heated 2 gallons (took about 10-15 minutes, I didn't time it actually) to 152 and poured them into the mash to hit 1.17 quarts/lb.
- Mashed at 152 for an hour with 5 gallons RO water w/minerals added, hit mash PH at 5.4.
- Added another 3 gallons and overshot a little to hit 171F. (was this my first mistake?)
- First runnings ~1.060 SG via refractometer (This is where I should have realized something was up... but thought nothing of it) It was at this point I DID notice there was an inch or so of liquid on top of a very compact grain bed. I mixed the grain bed up and it fluffed up to above the water level.

- Sparged and collected ~5.5g wort.
- Added another 2gal and overshot mashout temps again at 172F,
- Collected another 2gal liquid ~1.030 SG via refract.

For some reason I didn't think twice of my lack of mash efficiency and figured I would hit my target 1.094 (1.107 after dextrose addition) during the boil, but my OG into fermenter ended up being (don't laugh...) .... 1.074. If I had thought about it during my first runnings, I might have been able to reheat them and pour them back into the mash and see if I couldn't extract more sugars.

Any suggestions though? Did I get some crazy channeling that I should have considered? Should I have thrown in those couple handfuls of rice hulls I have been holding onto for a rainy day? Did I get some doughballs that I must have missed by dumping all my grain in at the same time, even though I *thought* I stirred it rather well?

My last Wit had excellent efficiency (low 80%'s), but the porter I did before that suffered from a similarly horrendous efficiency level (something like 34%), I need to learn to make sure I don't repeat this, because I'm effectively throwing money into the compost!

Appreciate any insight guys.

 

[olotti]

It just seems off the bat you didn't get all the sugars to convert out of the mash whether that was to thick of a mash or maybe u didn't mash long enough, I'll do a 75-90 min mash for higher gravity beers with a 1.25qt/lb ratio in the same mlt. The 3 gal mash out at 171 is fine as from what Ive read 172-175 is the real cutoff and that'll only add astringency from the mash not effect the overall conversion or efficiency. I'd also look at like u sid there may have been some channeling especially if there was water still sitting on top of the grain after collecting. Maybe things just didn't get mixed well enough, what do u use to stir the mash. I bought the wood dowel mash stir from nb and it helps so much especially with the thicker mashes with higher gravity beers. Look at it this way you live and learn and if the FG drops a little which it should with the sugar and I'm assuming yeast starter you'll still get a dble ipa and next time you just tweak a few things, take your time and pre plan water ratios and it'll all turn out good.

 

[doug293cz]

I recently posted some information that may help you diagnose your mash efficiency problems. Check it out here.

With batch sparging, channeling is not an issue. It only applies when fly sparging. Also when batch sparging, it is critical to stir the mash aggressively prior to initial run off, and after each sparge water addition. This helps insure that you have as much sugar in the drainable wort as possible, and the minimum amount left in the grain particles after run off. Finally, you should target your strike water and sparge water volumes to obtain equal run off volumes, rather than targeting a particular strike water to grain wt ratio. Equal run off volumes maximize the effectiveness of batch sparging.

Brew on