Hop Dry picture tutorial - Page 7 - Home Brew Forums

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05-29-2012, 12:59 PM   #61
wsender
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Perhaps this has been covered somewhere else, or it's common knowledge, but I haven't seen it anywhere so I thought I'd add it to this thread.

If you're shooting for 5-15% moisture then you should be aiming for 25-35% of your original mass. Just thought I should put that up here in case it hasn't been covered elsewhere.

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06-04-2012, 02:13 AM   #62
zrule

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Illinois
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Quote:
 Originally Posted by wsender Perhaps this has been covered somewhere else, or it's common knowledge, but I haven't seen it anywhere so I thought I'd add it to this thread. If you're shooting for 5-15% moisture then you should be aiming for 25-35% of your original mass. Just thought I should put that up here in case it hasn't been covered elsewhere.
What does this mean. I had to throw all my hops out last year as I did not get them dry enough. I used a box with a screen attached that would hold about threee gallons of hops. The hops were 2-3 inches deep and I used a fan to blow ambient temperature air. I would measure a small sample of hops at the beginning and monitor until I was below 20%. I would occasionally stir them. To measure the moisture, I would pick out a sample of 20 hops of differing sizes.

06-05-2012, 11:35 AM   #63
GVH_Dan

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Quote:
 Originally Posted by zrule What does this mean.
I'm not sure if I've posted this in this thread or just elsewhere, but here's the math behind the reduction in weight to 1/4 to 1/5.

The basic equation for determining moisture content of anything (hops, hay, herbs, etc.) is:
M% = ((Ww ‐ Wd)/ Ww) x 100

M% = moisture content(%)
Ww = wet weight of the sample
Wd = weight of the sample after drying
If you want to know the moisture content, take a small sample and weigh it to get Wet Weight (Ww). Then get the moisture out. Either bake it or put it in a microwave to pull out the moisture. When you are sure it is completely dry, that is your Dry Weight (Wd). Now plug it in to see your starting moisture content.

I wouldn't use that Dry Weight sample in your beer, though. They are extremely dry, crumbly, the lupulinic resins have changed and you will probably burn them the first few times you try.

The problem for the homegrower is that you would need most of your crop to get an accurate enough reading of the moisture content...nearly a 1/3 of a gallon of hops if you have a balance that goes to 2 decimal places when using grams. So it is somewhat pointless.

Instead, let's assume the starting moisture content is 80%. (I have seen from 93% when picked in the rain down to 74% for some smaller cones. So 80% is pretty much the middle.).

Let's pretend we have a 1/2 of a pound of cascade that we picked out of the backyard. Since we are assuming that it starts at 80%, we can use the above formula to calculate the Dry Weight....0.1 pounds.

Now let's say we want to dry down to a final moisture content of 10%. (Commercially, we shoot for 8%, but 10% is fine since you aren't pelletizing.) with a moisture content of 10% and a Dry Weight of 0.1 pounds, the "Wet Weight", which in this case is the weight of the dried hops, would be 0.111 pounds.

Working that out, the ratio of beginning to end weight is 0.111/0.5 = .222 or another way to say it is that the final weight of the hops is somewhere between 1/4 and 1/5 the starting weight.

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06-05-2012, 11:38 AM   #64
GVH_Dan

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Quote:
 Originally Posted by zrule I had to throw all my hops out last year as I did not get them dry enough. I used a box with a screen attached that would hold about threee gallons of hops. The hops were 2-3 inches deep and I used a fan to blow ambient temperature air. I would measure a small sample of hops at the beginning and monitor until I was below 20%. I would occasionally stir them.
zrule, you main problem here was that the hops bed is too deep. At 2-3 inches deep, a box fan would not be able to blow through the whole bed so only the stuff on the top and bottom would be dry and the hops in the middle would stay pretty wet.

06-05-2012, 02:36 PM   #65
wsender
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Quote:
 Originally Posted by GVH_Dan I'm not sure if I've posted this in this thread or just elsewhere, but here's the math behind the reduction in weight to 1/4 to 1/5. The basic equation for determining moisture content of anything (hops, hay, herbs, etc.) is: M% = ((Ww ‐ Wd)/ Ww) x 100 M% = moisture content(%) Ww = wet weight of the sample Wd = weight of the sample after dryingIf you want to know the moisture content, take a small sample and weigh it to get Wet Weight (Ww). Then get the moisture out. Either bake it or put it in a microwave to pull out the moisture. When you are sure it is completely dry, that is your Dry Weight (Wd). Now plug it in to see your starting moisture content. I wouldn't use that Dry Weight sample in your beer, though. They are extremely dry, crumbly, the lupulinic resins have changed and you will probably burn them the first few times you try. The problem for the homegrower is that you would need most of your crop to get an accurate enough reading of the moisture content...nearly a 1/3 of a gallon of hops if you have a balance that goes to 2 decimal places when using grams. So it is somewhat pointless. Instead, let's assume the starting moisture content is 80%. (I have seen from 93% when picked in the rain down to 74% for some smaller cones. So 80% is pretty much the middle.). Let's pretend we have a 1/2 of a pound of cascade that we picked out of the backyard. Since we are assuming that it starts at 80%, we can use the above formula to calculate the Dry Weight....0.1 pounds. Now let's say we want to dry down to a final moisture content of 10%. (Commercially, we shoot for 8%, but 10% is fine since you aren't pelletizing.) with a moisture content of 10% and a Dry Weight of 0.1 pounds, the "Wet Weight", which in this case is the weight of the dried hops, would be 0.111 pounds. Working that out, the ratio of beginning to end weight is 0.111/0.5 = .222 or another way to say it is that the final weight of the hops is somewhere between 1/4 and 1/5 the starting weight.
I think we arrived at similar destinations through different paths. However, I don't think you took into account the unchanging mass of the solid mass of the hops.

I remember reading somewhere that fresh hops are 80% water and 20% solid mass. So if we take an ounce of fresh hops, we have 0.80 ounces water and 0.20 ounce of solid mass. Upon reducing the moisture content to 10% we can defer that the make up of the overall mass will be 0.10 ounces water and 0.20 ounces solid mass, providing the drying process removed ONLY moisture. Our ending mass would be the combination of the final moisture mass and the solid mass, 0.30 ounces.

This is scale-able so therefore to achieve 10% overall moisture you want to shoot for 30% of your original mass.

In general terms....

06-05-2012, 04:40 PM   #66
drummstikk
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Quote:
 Originally Posted by wsender Upon reducing the moisture content to 10% we can defer that the make up of the overall mass will be 0.10 ounces water and 0.20 ounces solid mass
Oops! Moisture is measured as a percentage of current weight, not initial weight. Your example is consistent with the equation you posted, but that's not how moisture is measured.

The reason you don't measure moisture as a fraction of the original weight is that the original moisture content of the hops can vary quite a bit, depending on weather and humidity.

In your example, once you dry down an ounce of hops (that started at 80% moisture) to 10% moisture, the dry mass would still be .2 oz as you pointed out, and the water mass would be 10% of of the current (not the initial) mass. So you would write (ww -.2)/ww = .1 and solve for the wet weight, ww = .222 oz. The total weight at 10% moisture as a fraction of the total weight at 80% moisture is .222 oz / 1 oz = 22.2%

You both took into account the dry mass of the hops, but you just want to be sure you're expressing moisture as a fraction of the current mass of the hops, not the mass when they were picked.

06-05-2012, 05:03 PM   #67
GVH_Dan

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Right...either way, the point is you are not dry until you are at a weight at least 1/4 of the original starting weight or less. But if you are less than 1/5, you are running the risk of being over dry. By over dry, I mean bracts falling off, strig snapping, lupulin falling out.

Just some further advice, you should get to under 15% to prevent spoilage. This is easily possible with using plain old air...no heat...no dehumidification...just air and time. You can tell when you start getting close because the bracts will start to open up like a pine cone. I usually see this start in the 22% to 17% range.

07-28-2012, 03:42 AM   #68
jamnw
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tn
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I just picked my first hops. I dried them on a screen with a fan blowing on them and a dehumidifier in the room. The humidity was 60%.
I dried them for two days, and they were very dry.
they seem to have lost all their cascade aroma. They smell like "grass" to me, not that kind, but regular old grass.
I think I let them stay too long on the vine. They were pretty dry when I picked them.

Any thoughts suggestions?
thanks

08-01-2012, 12:09 AM   #69
NorthSide
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Chicago, illinois
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my first year hops didn't have that great of aroma either when dried, i'm hoping the 2nd year is better...

08-31-2012, 02:45 PM   #70
CaptnCully
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Feb 2012
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Quote:
 Originally Posted by Randar Other tips you can utilize... - Use a space heater to help raise your temps into the 100-130 degree range. (works great if you live in a hot climate with a garage that isn't well insulated!) - flip the filters so the side nearest the fan doesn't overdry relative to the opposite end BTW, this is essentially Alton Brown's method for herb drying applied to hops.
I did this and the outside of the hops got really dry and crumbly before the center was even close to dry. Maybe I did not have enough air flow... temp was 128*