Original Gravity doesn't measure up

[kage72]

MEB, I salute you, rarely-sober friend from the Southern Hemisphere :

I read this site about batch sparging:

http://www.bayareamashers.org/content/m ... arging.htm
Is this acurate to your procedures? and can you reach high efficiency?

After research and the help of all you kind folks, I have decided that
1) I mash with WAY too much water (easily corrected!)
2) my sparge method is half way between fly and batch sparging. I dump a lot of water into the mash tun at once, drain it fairly rapidly, and dump more when the level of water drops to 1 inch above the grain. This way, I can run errands or entertain my 2-year-old while sparging. But my mash tun won't accomodate the full amount of water all at once, so I essentially have to break my batch sparging into , 5 batches. Also, I don't stir the grains, as the above artical suggests. I bet that would increase efficiency, but I would fear leaching some tannins.

I think my next attempt will be my return to fly sparging, putting water in slowly and constantly, trying to match inflow to outflow and making sure the sparge lasts at least 1 hour. Also I have put a grain mill on my Christmas list.

 

[MEB]

Good on ya K


This thread may be worth reading K.

http://www.thehomebrewforum.co.uk/viewtopic.php?f=23&t=682&hilit=+V+arm

 

[Vossy1]

and can you reach high efficiency?

Generally batch sparging is LESS efficient than fly sparging. Average for fly 80-85%, batch 70-75%

Also, I don't stir the grains, as the above artical suggests. I bet that would increase efficiency, but I would fear leaching some tannins

Yes stirring does increase efficiency. Think of all the upturned husks as cups collecting sugar, unless you turn them over the sugar will remain in the cup.

Regards tannins, yes the mechanical action of stirring may release some tannis, but I haven't had this problem.
It's just as easy to over sparge and release tannins when fly sparging.
There is a school of thought that says a better quality of wort can be collected by deliberately being inefficient.

I get around 74% efficiency from batch sparging, and I'm happy with that.

 

[kage72]

Vossy,
What formula do you use for extraction - something that has (OG/litre)/(kg of grain). (I can do metric too!)

I remember some formulas from a brewing book I used to have, but I lost the book in a flood.

Do you know the formulas or do you get the numbers through software?

Cheers!
Kage

 

[Aleman]

Commercial Mash tuns have mechanical rakes in them to do just what V described . . . . Well the big tuns do

 

[BrewStew]

Aleman, are the rakes stopped a while before the sparge to let the grain rest? or are they immediately turned off litterally just before they sparge? or even kept on for the sparge?

 

[Aleman]

The simple answer is yes

It really depends on the plant downstream of the Mash tun, often you'll have a centrifugal filter which removes the solid debris from the sweet wort. This of course means that you do not need to recirculate, and you can also keep the rakes running while you fly sparge. The new mash tuns actually spin the grain, like a twin tub washing machine, to really extract every last drop of liquid . . . and extract producing very high efficiencies.

Less modern plants stop the rakes and recirculate as we do, before fly sparging.

I can't think of a commercial brewery that actually batch sparges these days . .. it is just too wasteful

 

[BrewStew]

cool!

i'm ever so tempted to get a washing machine motor or similar and get a local steel fabricator to manufacture something to stir the grain in my thermobox, cos i reckon i had oodles of dough balls on my last brew, and it was such a pain doughing in 20kg of grain!

what do they look like? got any pics from your travels around the breweries?

 

[jamesb]

cool!

i'm ever so tempted to get a washing machine motor or similar and get a local steel fabricator to manufacture something to stir the grain in my thermobox, cos i reckon i had oodles of dough balls on my last brew, and it was such a pain doughing in 20kg of grain!

what do they look like? got any pics from your travels around the breweries?

Why not bodge together a hopper and a chute and mix the grain in with the liquor when it's dropping down the chute, then all you really need is a quick stir and eskimo_bob's your uncle. There's various ways of doing that.

 

[BrewStew]

a chute is too much of a palava... plus it means lifting 20kg of grain above my head. dont fancy that!

 

[jamesb]

a chute is too much of a palava... plus it means lifting 20kg of grain above my head. dont fancy that!

Wimp!

:P

 

[BrewStew]

hehehehe

when you've felt the pain of a slipped disc playing up the way my back does, and held in the scream... you wouldn't be calling me a wimp :twisted:

 

[Aleman]

what do they look like? got any pics from your travels around the breweries?

No no pics as I wasn't all that interested in that side of it at the time

Think of a 4 armed spinny sparger, but instead of holes either spikes (up and down) or twisted 'vanes' (blades)the thing turns quite slowly, a few revolutions a minute . . . . Deeper mash tuns have these at different heights

 

[Vossy1]

Vossy,
What formula do you use for extraction - something that has (OG/litre)/(kg of grain). (I can do metric too!)
I remember some formulas from a brewing book I used to have, but I lost the book in a flood.
Do you know the formulas or do you get the numbers through software?

I used to do it long hand, but now I use Beersmith brewing software.

 

[kage72]

Update: thanks to all the help from you kind folks, on today's brew I achieved the recipe's OG exactly.

Here is what I changed: Reduced the water in mash to the volume you suggested. Fly sparged, roughly matching inflow to the MT with outflow. Recirculated for 15 minutes (after reading your site's link the the HERMS guy.)

As we say on this side of the pond, I'm a happy camper. :thumb:

One strange thing, however (I have yet to have a brewing day without some problem!):
I measured precisely the amount of wort sent to the kettle 6.25 Gal, (23.5 L), I boiled for 1 hour, but must have boiled too vigourously, my volume after boil was 4.7 Galons (17.8 L). This seems like a LOT of loss to steam, but I was following instuctions to keep at as high a boil possible without boiling over. That's almost 25% less, does this seem realistic? Am I going nuts?

Also here is how I calculated my final volume by using hydrometer readings (pre-boil volume in the kettle was measured precisely and known, and hydrometer readings pre and post-boil were known)

pre-boil Kettle Vol * Gravity before Boil = After Boil Vol * After Boil Gravity
6.25 * 42 = x * 56
x = 4.69


Kage

 

[Vossy1]

Glad to hear you hit your target OG k

One strange thing, however (I have yet to have a brewing day without some problem!):

That's not strange, that's perfectly normal

I measured precisely the amount of wort sent to the kettle 6.25 Gal, (23.5 L), I boiled for 1 hour, but must have boiled too vigourously, my volume after boil was 4.7 Galons (17.8 L)

Is that 17.8ltr of cooled wort in the fv K, and what was your target volume post boil, ie, into the fv?

Your evapouration rate depends on a lot of factors, as you already know.
You will lose some volume to your kettle, some will be absorbed by the hops and some will be lost to the wort volume shrinking as it cools.
Loss to whole leaf hops can be roughly worked out as 600ml of wort per 100g of hops.
Your kettle losses can be roughly worked out by filling it with some water, then opening the tap. When the flow stops, shut the tap and measure what's left in the kettle.
Cooling loss can be worked out on some beer software, but if you cool in the kettle and it's well marked you can see how much you lose there.
Remember though if using an immersion chiller that it will increase the volume when added to the kettle, and you could do with knowing what volume it displaces to fine tune your system.
Cooling loss is not really as important as that of the hops and kettle dead space.
Once you know the figures above you can start to fine tune your brew day, but as long as your beers good in the mean time, don't get to hung up on it

 

[kage72]

I was aiming for 5 Gal, (19 L.)

I used pellet hops. (not whole leaf.)

Anyone have an ingenious way to dispose of 10 lbs (4.5kgs) of water soaked 150 deg F (66 deg C) grains. They tend to melt through my large garbage bags. What a mess!

Kage

 

[Vossy1]

If you wanted to Kage you could just up your next pre boil volume by 1.2ltr to make the 17.8 up to 19ltr.
I'm not sure about loss to pellets as I don't use them but I'm sure someone on here will be able to tell you what it is.
Until you know the losses to your system it's hard to say if your boil is too vigorous. About 10% per hour is average (if there is such a thing).
One of the possible draw backs of a really vigorous boil is that it may darken your beer/impart a toffee taste, due to scorching of the wort, but if that doesn't bother you it's really quite a trivial detail.

Regards the grains, I double wrap mine in garbage bags once they have cooled down.
Some folk compost theirs in the garden, some feed it to pigs/chickens etc.
Have a look here for grain disposal clicky