Time and/or grind?

[GilesTH]

I brewed my third all grain batch on Saturday, and I really thought I had my efficiency close to worked-out. On my first brew, I hit 68.5% and on my second one came it at 71.4% (which is what beersmith told me based on OG AFTER I added corn sugar). But my most recent batch came out at 60.3%, making me miss my target gravity by 6 points.

I changed TWO things this time around: I mashed for 45 minutes instead of 60, and I only stirred the mash on dough-in instead of periodically. Would those have effected the efficiency at all, or am I looking at how fine the grain got milled at the HBS? I don't know if the store changes their mill at all, but I don't mess with it since I don't know what I'm doing.

But this bothers me. I was shooting for a 1.060 beer that only came out at 1.054. OH, and my grain bill is 93% US two row, 3.5% special b, and 3.5% light munich. Would soaking the grains longer have helped? Or should I try for a double-mill next time and expect and over-the-top gravity?

[snowcapt]

You absolutely need to stir it more. Stirring the mash means more contact with the water. More contact with the water ensures that the starches will be better exposed, allowing for better conversion.
Without stirring the mash, it just settles to the bottom. In doing so, the water just sits on top of the mash, doing nothing. Move that shit around and expose those lil starchies!
Cheers!
Soon enough, it'll be second nature.

[GilesTH]

You absolutely need to stir it more. Stirring the mash means more contact with the water. More contact with the water ensures that the starches will be better exposed, allowing for better conversion.
Without stirring the mash, it just settles to the bottom. In doing so, the water just sits on top of the mash, doing nothing. Move that shit around and expose those lil starchies!
Cheers!
Soon enough, it'll be second nature.

Good to know. That was one of those "doh!" moments for me. When I dough in, I always add the water to the mash tun then pour the grains in while stirring the mash to mix it up. But, yes, I realize I should've stirred about every 15-20 minutes. I'll make sure I do that in the future .

[Bugeater]

Stirring every 20 minutes or so can help, though I don't do it and consistently hit 75-80%. I would see an inconsistent crush as the #1 suspect. If you are there when the LHBS mills it, take a look after the first pound or so to make sure you only have the occasional whole kernel getting through but not completely pulverizing the husks. Sometimes the gap will drift a bit on some mills after running a high volume of grain. So the mill might be a little off.

Back to stirring, folks using a paddle or big spoon will still leave some clumps in the mash even though you think you stirred the crap out of it. A heavy duty wire whisk (available at good kitchen stores or at any restaurant supply shop) will cut through any dough balls almost instantly. Those dough balls will wreak havoc on your efficiency.

The 45 minute mash won't affect your efficiency unless you have really screwed up somewhere else and didn't get good conversion. Conversion is generally "complete" in as little as 20-25 minutes. You don't want to stop there, though. At that point you are going to have a large amount of long chain sugars that the yeast will struggle with. The longer time will give the enzymes the time necessary to continue breaking those chains into more fermentable sugars. An hour is pretty much the optimum time. Longer times, typically 90 minutes are for when you need the wort to be especially fermentable in beers like barleywines and strong scotch ales where the yeast has to cope with high alcohol as well as long chain sugars. I shy away from only doing a 45 minute mash due to the potential problems there.

[GilesTH]

Stirring every 20 minutes or so can help, though I don't do it and consistently hit 75-80%. I would see an inconsistent crush as the #1 suspect. If you are there when the LHBS mills it, take a look after the first pound or so to make sure you only have the occasional whole kernel getting through but not completely pulverizing the husks. Sometimes the gap will drift a bit on some mills after running a high volume of grain. So the mill might be a little off.

Back to stirring, folks using a paddle or big spoon will still leave some clumps in the mash even though you think you stirred the crap out of it. A heavy duty wire whisk (available at good kitchen stores or at any restaurant supply shop) will cut through any dough balls almost instantly. Those dough balls will wreak havoc on your efficiency.

The 45 minute mash won't affect your efficiency unless you have really screwed up somewhere else and didn't get good conversion. Conversion is generally "complete" in as little as 20-25 minutes. You don't want to stop there, though. At that point you are going to have a large amount of long chain sugars that the yeast will struggle with. The longer time will give the enzymes the time necessary to continue breaking those chains into more fermentable sugars. An hour is pretty much the optimum time. Longer times, typically 90 minutes are for when you need the wort to be especially fermentable in beers like barleywines and strong scotch ales where the yeast has to cope with high alcohol as well as long chain sugars. I shy away from only doing a 45 minute mash due to the potential problems there.

I was hoping for some longer-chain sugars because every brew I make drops WAY below my target FG. My mild was supposed to be about 1.008 or 09 and ended up closer to 1.005. Jamil said the Saison yeast from White Labs ALWAYS stalled out for him around 1.008 or even 1.012, so with my Saison, I was shooting for 08 or maybe as low as 06 and hit 1.004!

This beer is supposed to be an IPA (one or two points short to be "within style"), so I want it to stop closer to 1.008.

On that note, is that why there's about six inches of bubbling foam on top of my ferment? I've never seen THAT much activity before! Or would that be due more to the fact that I'm having trouble dropping the temp down to 68f? It's hovering around 71 or 72 right now.

[Ozwald]

about six inches of bubbling foam on top of my ferment? I've never seen THAT much activity before! Or would that be due more to the fact that I'm having trouble dropping the temp down to 68f? It's hovering around 71 or 72 right now.

I've had thicker krausen than that even.

The higher temps could likely be affecting the attenuation though.

[mickp]

I'm also pretty much a non-stirrer once I've mashed in and I hit 70-75% consistently. how you dough in can make a big difference...I'm able to flow water and grain into my 10G cooler together and keep a close eye to make sure everything gets wet right away . But I think Bug has the best answer for something to check initially. I had a lot more variation in the days when I had the LHBS do the grind.

I'm curious about the relationship between these "long chain sugars" and efficiency. I don't think conducting a mash that is preferential to longer chains will impact efficiency, given that you mash for long enough. I think a sugar is a sugar for gravity reading purposes, or am I wrong?

[GilesTH]

I'm curious about the relationship between these "long chain sugars" and efficiency. I don't think conducting a mash that is preferential to longer chains will impact efficiency, given that you mash for long enough. I think a sugar is a sugar for gravity reading purposes, or am I wrong?

Yeah, you have that right. In fact, the long chains break down quicker, meaning a heavy-bodied beer will convert faster. (This is because of the the alpha amylase, I think. The 154f-158f range.) But the 146f-153 will get shorter chain sugars which are more fermentable, producing the dryer beers. Because of how the enzymes work, the lower temps take longer to convert.