PM Efficiency Help

I brewed a wit this past weekend and missed my OG by a good bit, 1.043 instead of 1.050. Not sure what went wrong.

The ingredients:

3.5 lb. 2-row
3.15 lb. wheat
0.35 lb. flaked oats
1.5 lb. Wheat DME
2 oz. Tettnang hops
0.75 oz. bitter orange peel
1 oz. sweet orange peel
0.75 oz. coriander seed (crushed)
Wyeast Witbier (don’t recall the number)

The procedure:

Strike water was 9 quarts @ 164F and mash temp was 150F to start. After 20 minutes I was getting 147-149F and after 40 minutes temp was about the same, maybe a bit lower. I mashed out with 3 quarts of boiling water, vorlaufed and drained right away. Sparged with 6 quarts @ 180F which brought the grist up to 163F after it was stirred in, let that sit for 10 minutes, vorlaufed and drained. Total runnings were 3 gallons. Brought that to a boil and added the hops, boiled for 45 minutes and added the DME, boiled for 15 minutes and added the orange peels and coriander, boiled for 5 minutes and cooled. Added to carboy with enough water to make 5 gallons and agitated thoroughly before pulling a sample with my wine thief.

I’m going to brew again this weekend, a hefe, but the ingredients will be the same ratio in terms of grains to extract. My guess at this point is that my temp was too low. The grains had been refrigerated since I bought them a few days before brewing but they had been out of the fridge for a good hour or two before hitting the water. My tun was pre-heated with hot, 125F, tap water.

If there’s any other info you guys need let me know. I think for this weekend I’m just going to shoot for a strike water temp of 168ish and see what that gets me.

are you using a program to calculate your OG, or just running the numbers on paper?

LOTS of things come into play for efficiency: in your mashtun is it a false bottom, a manifold, or a braided SS line? each has pros and cons, including sacrificing efficiency for low risk of a stuck sparge.

I'm at work or I'd plug your recipe into beertools.com to see what efficiency with the above would yield 1.050 OG.

the crush of your grain could be to blame too.

The 1.050 came from Beersmith.

My tun is a 5G cooler with a steel braid. Would it be more efficient to go with a manifold, I'm not opposed to switching it out?

Not sure whether the crush is good or not, don't have anything to compare it to.

I calculate your efficiency as 63% using Beer Recipator. Have you calculated this before using the same set-up and process?

Your mash temp will not afffect efficiency by much as long as you are within a reasonable range of your target. It will affect the final gravity as it has a profound affect on fermentability.

One likely cause is the volume of water you are working with. I'm assuming you are limited by the size of your boil pot. I would guess you still have some fermentables in your grain bed after your second sparge. If you could use larger volumes you would get more of those sugars out. For example when I brew a 1.035 beer using about 8# total grains and boil volume of 7.5g I get close to 85% efficiency. When brewing a 1.050 beer using about 11# of grain and the same 7.5g boil volume I get 70% efficiency. If I increase my boil volume to 8.5g and therefore increase my sparging volumes I get about 80% efficiency. Of course I need to boil for an extra hour - thats the compromise. I would prefer not to boil so long so I increase my grain bill to compensate for the reduced efficiency.

No, I haven't done any efficiency calcuations on prior batches. This is only my 4th PM batch. Of the other three, one also had a really low OG, one had a much higher than expected OG but I think that was because I misjudged how much the molasses I added would affect the OG and the other, my first PM, was a hefe that had a normal OG of around 1.050, don't have the exact number with me.

You're right, I do have a limited boil volume. I have a 16 quart pot so 3-3.5 gallons is about my max. I will be getting a bigger pot but it's still a few months off.

I've been going with 7# of grain because I thought the 1.28 quart/pound was a good ratio. I could get that up to 2 quart/pound by dropping to 4.5 lb. of grain. However, if the water to grain ratio is the issue, I have to assume my yield from 7# at 1.28 would be the same or close to 4.5# at 2, right? That being the case I still need to up my DME in order to compensate. What I may do is plug 4.5# into Beersmith with a 70% efficiency and see how much DME is called for to get to a normal OG and go from there. Would that be the best way to approach this? Obviously I could always just drop my efficiency in Beersmith and add DME to compensate but that seems like a waste of grain.

I'm a PM brewer with the same MLT as you. I also have had some batches come in too high or too low. It seems to be more consistant now that I always do 3.5 gallon boils, I only top up with enough water to hit my OG (instead of always topping up to 5 gallons), and I set my efficiency to 68% in Beersmith. The crush could definitely be the problem though. I'd also recommed trying to use closer to 3lbs of extract and then building it up to your target gravity from there. As a side note, when I have fallen short of my target OG I usually add some sugar to bump it up in primary. It dries the beer out but I'm ok with it since it kind of balances out the extract sweetness...

The starches don't fully gelatinize below 149F and can take 40-60 minutes at that temperature. If they don't gelatinize, they can't dissolve and be converted.

david_42 said:

The starches don't fully gelatinize below 149F and can take 40-60 minutes at that temperature. If they don't gelatinize, they can't dissolve and be converted.

Click to expand...

The flaked oats should be pregelatinized.

Roterdrache: You have 3 choices. Increase the grain bill - but you will be decreasing your efficiency; Add more DME which is probably your best choice; Get that bigger pot and go to a full batch boil.

did you check the og with an actual hydrometor ,and at what temp did you check it and did you make corrections in the reading after you checked exact temp of cooled wort ?

I can see I have some decisions to make before I brew this weekend. Given what david_42 said regarding the temp at which the starches gelitinize and the fact there's a good chance my mash was at or below that temp for a good part of the 60 minutes I'm leaning towards trying my current system one more time and making darn sure my temps are high enough. Plus, it's not like the beer's not drinkable or tastes off, it's just not as potent.

If this weekend I end up with the same low OG I will probably go with more DME which I really hate to do because I'm trying to use as little DME as possible. But I'd rather user more DME than essentially waste grain.

bull...Yes, I used a hydrometer and the temp when I took my reading was @83F and I corrected for that by adding .005 to my reading.