Lower gravity

I'm just getting into all grain brewing. And I'm wondering why my gravity is lower. How long should sparging take. The beer I brewed yesterday was suppose to have a gravity of 1.078. The gravity I got was 1.064. I know it's not a big deal it will just have less alcohol. But I just want to know why I'm getting such low gravity. Am I not sparging long enough or what. I think the sparging only took me about 30 mins. my Temps for mashing were pretty dead on. Maybe 1 or 2 degrees high but nothing to be concerned about I think. And help is appreciated

Well, I'm still pretty new to this, but that could be caused by a couple of things. First and foremost, your crush could be poor leading to poor efficiency. What's the recipe? Do you stir after adding the sparge water? Do you recirculate?

Assuming you have your process pretty well dialed in and know your efficiency, once your gravity gets up above 1070-ish it's typical to see a drop in mash efficiency. I usually get about 80% effiency for a standard brew but I lose about 4 points in efficiency for every 10 gravity points over 1065. I just account for it in my calculations or plan on adding some sugar to the boil to compensate.

The recipe is a stone ruination clone recipe. 14.6 pounds 2 row and 1 pound crystal 20L. Then 2.25 ounces magnum and 1.5 ounce centennal. It was a 90 minute boil. I do stir during the mash and the sparging. No I don't recirculate.

what efficiency did you use for calculating your recipe? If you assumed an 85% efficiency, but only get 78% in real life, that will account for the numbers being low. you'll have to adjust your assumed efficiency. there may not be an actual mash issue.

Crush is the answer to the question "where should I start looking for a solid reason for my low efficiency?"

Other reasons (some mentioned already):
Higher gravity beers and darker beers can suffer eff loss above 1.070

Thermometer is not calibrated.

These come to mind, but I would still check out the crush quality before anything else.

not yet

serrano07 said:

How long should sparging take.

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I dump in my sparge water, stir like it owes me money, let it sit for 10min, then drain, and repeat if I'm still not at my preboil volume.

Might be your crush on the grains as mentioned before for a cause on the lower gravity. If you mill your own you might try crushing with a narrower mill gap if you can adjust your gap. Or you could try running them through the mill twice. Or ask your LHBS to mill twice if your having them crush for you. Just my .02

I too am going to go with crush. It doesn't sound like there is much else that could be wrong unless the recipe was calculated at a higher efficiency than you achieved. Then again, it could be the crush that caused that.

brewkinger said:

Thermometer is not calibrated and you mashed at higher temps (sweeter and less fermentable wort)

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Just for clarification, I don't think this would effect OG. Unless the temperature was so far off, that the enzymes were denatured before conversion was complete. That seems unlikely to me.

So you'd still theoretically have the same amount of sugar dissolved in solution, but the ratio of short- to long-chain molecules would vary. Unless I'm missing something in your post?

Can someone confirm my thinking on this? BioChem isn't my strong point.

serrano07 said:

The recipe is a stone ruination clone recipe. 14.6 pounds 2 row and 1 pound crystal 20L. Then 2.25 ounces magnum and 1.5 ounce centennal. It was a 90 minute boil. I do stir during the mash and the sparging. No I don't recirculate.

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You stir during sparging? So you batch sparge, adding your sparge water all at once, stir, then vorlauf and drain? Or do you do something else?

djfriesen said:

Just for clarification, I don't think this would effect OG. Unless the temperature was so far off, that the enzymes were denatured before conversion was complete. That seems unlikely to me.

So you'd still theoretically have the same amount of sugar dissolved in solution, but the ratio of short- to long-chain molecules would vary. Unless I'm missing something in your post?

Can someone confirm my thinking on this? BioChem isn't my strong point.

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Yes, mash temperature generally doesn't effect gravity, only fermentability. Unless your temperature is so far off that you don't have complete conversation.

When someone says "mash efficiency problem" my first thought is laughtering efficiency. Laughtering efficiency is basically wort out divided by water in. What volumes were used?

It was 4 gallons strike water at 165. Which once I added the grains it was at 154. Then it was about 6 gallons sparging at 170. With sparging I petty much sprinkled the water on top just to keep my liquid level above the grains. Then once I got my pre-boil volume I stopped.

60 minute mash rest as well

With 4 gallons of strike water and 15.6 lbs of grain it sounds like you have a pretty thick mash which would mean a lot of wort is tied up in the grains. It's also going to be hard to get everything wet and get good runnings with a thick mash. (channeling may be an issue) If your pre boil volume was 6 gallons that could explain the efficiency of about 60% instead of 75%.