Calculation questions

[buzd]

Ok, so after a couple of extract batches, I am going to switch to All Grain. It looks like I mostly just need a bigger kettle and a mash tun (I thought about it, and don't really want to do BIAB). My smaller extract kettle will be good for heating sparge and strike water.

I'm going to start with doing a few Smash batches, so I can really see what kind of malts and hops I like. Plus I think that will be good practice for the AG process.

I will pretty much be doing 5/5.5 gallon batches (as I have two carboys that size, and it seems to be a manageable amount for what I'm working with).

My question is, how do I figure out how much grain/water to use for strike/sparge etc? Working backwards, I guess I need to boil about 6.5/7 gallons of wort before boil off, and some water will be absorbed by the mash right? Say 1-2 gallons? So that's about 8 gallons of water? How to I divide that between mash and sparge? 5/3? 6/2? How do I calculate how much grain to use? (I will probably start with Maris Otter or 2-row).

I found the IBU calculator, so I think I'm good on the hops calculations (will probably add 1oz at 60, and then some late additions, as I like moderately hoppy pale ales, mostly).

Thanks for any advice.

 

[Pariah3j]

So Buzd - I'm in your boat right now, about to make the swap to AG. Just got the bigger Kettle and a Mash Tun - I tried BIAB and it was ok but I have no way to hoist the bag so it was kind of a pain, so I decided to go all in for AG.

I'm curious the answer from some AG vets on how they handle this. The way I had planned on doing it was rough guestimations like you are doing and then adding an extra gallon or so to my calculations as to make sure I have plenty.

 

[kh54s10]

Get a copy of Beersmith or use an online recipe builder.

I mash with what Beersmith recommends. It it between 1.25 and 1.5 quarts per gallon. I drain the mash and measure how much I have collected. I then subtract that from what I need for boil off. I then sparge with about half still needed and measure my volume again, this allows me to accurately add the remaining needed for sparging.

 

[billl]

There is lots of software out there to help. It's well worth the $20.

If you want to do it by hand, grain absorbs about 1/8 gallon per lb. You'll also have some dead space in your tun. You can measure that by just adding water to it and seeing how much doesn't drain.

So, you'll start out with about 1.25 quarts per lb of grain for your mash. Let's just say you have 10 lbs of grain for simplicity. That is 10 * 1.25 / 4 = 3.125 gallons of strike water. The grain will absorb about 1/8 * 10 = 1.25 gallons. Another 0.25 gallons might not drain from the tun. So, you'll get 3.125-1.25-.25 = 1.625 gallons out for your first runnings. If you need to start with 6.5 gallons, you'll need to sparge with 4.875 gallons total. If your tun can fit that much sparge, you can do it all at once. Otherwise, you could split it in half and sparge twice.

It's a really good idea to just heat up some extra sparge water and also have some DME on hand in case your efficiency isn't great. If you are concerned, you can do test boils with water to see how much you really need. Personally, I'd just say relax and take good notes. If you end up with 4 gallons of beer instead of 5, big deal. You'll know to add an extra gallon of water the next time. You'll undoubtedly need to make some corrections no matter how carefully you plan.

*** random extra warning - if you are used to cracking a beer as you start your brew day, you might want to hold off a bit. If you drink through 6 hours of brewing, you'll make a TON of mistakes.

 

[buzd]

Thanks for the replies, y'all. That helps a lot.

I downloaded the trial of Beersmith, and that appears to be exactly what I needed. It looks like you just adjust your ingredients until the parameters (ABV, IBU, etc) are at the target values that you want your beer to be, right? Really cool.

Thanks for pointing me in that direction. Will definitely be registering that software.

 

[Sailingeric]

A couple things that have helped since I went AG, is get a grain mill. Made a big difference on the few batches I have done since I got and I got a refractometer. Not needed but a very cool tool and better at reading the OG than the hydrometer.

 

[buzd]

Is it not sufficient to have my LHBS mill the grain?

And I already have a refractometer.

 

[kh54s10]

Is it not sufficient to have my LHBS mill the grain?

And I already have a refractometer.

It depends on the LHBS. Some mill well and consistently, others not so much.

You will probably want a hydrometer also. There are calculators for correcting refractometer readings with the presence of alcohol. Their accuracy is debatable.

Find all the instructional videos on Beersmith and watch them multiple times.

Take some time to set up your equipment profile. Try to figure out what any change makes. You will have to make tweaks over time to dial in for your system.

It is a great tool, but you have to learn how to use it properly.

 

[buzd]

It depends on the LHBS. Some mill well and consistently, others not so much.

You will probably want a hydrometer also. There are calculators for correcting refractometer readings with the presence of alcohol. Their accuracy is debatable.

Find all the instructional videos on Beersmith and watch them multiple times.

Take some time to set up your equipment profile. Try to figure out what any change makes. You will have to make tweaks over time to dial in for your system.

It is a great tool, but you have to learn how to use it properly.

Dammit, I meant to buy a hydrometer at the LHBS today, but I forgot. The one from my original kit broke in transit.

Thanks for the advice. Regarding the equipment, that's one of the reason I want to do a few Smashes. It will familiar myself with the different malts and hops and let me nail down some of the details on how my actual equipment performs. I need practice taking readings - with the extract kits I've done, I haven't bothered too much (broken hydrometer and all). 3 weeks in the fermenter is pretty much plenty, and so far, so good.

 

[doug293cz]

Calculations are best done starting from the desired end point (ie the volume you want to keg or bottle.) From there add the expected trub/yeast losses from the fermenter to get your target fermenter volume. Fermenter losses are typically about 10%, so if you want to bottle/keg 5 gal, you need to get about 5.5 gal into your fermenter. Fermenter losses vary depending on how much kettle trub gets dumped in the fermenter, amount of hops added to the fermenter, and how well your yeast strain compacts. You need to determine what your typical fermenter volume loss is based on your process and what types of beer you brew.

Next figure out your target post-boil volume. This will equal your target ferment fermenter volume plus your expected kettle trub losses. Trub losses can be a low as zero, if you dump everything into the fermenter. Or, they could be as high as 1 gal if you use a lot of loose leave hops and try to strain them and the break material to keep them out of the fermenter. Again, you need to determine your number based on how you brew.

Next figure out your target pre-boil volume. This is just your target post-boil volume plus your evaporation losses during boil. You can determine an approximate boil off rate for your system by putting a few gallons of water in your BK, and then boiling for a half hour at the same vigor that you boil your wort. Measure the post-boil volume, subtract that from the pre-boil volume, and multiply the difference by 2. This will be your boil off rate in gal/hr. For any given brew the expected evaporation loss is your boil off rate times the length of boil (in hours.)

Next figure out your mash tun undrainable volume. Do this by putting a couple of gal of water in your MLT, and then drain it in the same way you do when brewing. Measure the amount of water left in the MLT after draining. This is your undrainable or "dead" volume.

Next determine your total brewing water requirement (everything needed for mashing and sparging.) Total brewing water for batch sparging is equal to your target pre-boil volume, plus your MLT dead volume plus, the grain absorption volume. Grain absorbs about 0.12 gal/lb in a traditional MLT. To get total grain absorption, multiply your grain bill weight by 0.12 gal/lb. If you are fly sparging, you will need additional water sufficienct to leave the grain bed covered with ~1" of water at the end of run off.

If you are going to fly sparge, then you want to mash in at about 1.25 - 1.5 qt/lb.

If batch sparging you need to determine how to split up your strike vs. sparge water. There is no good reason to mash at a particular water to grain ratio, especially since thinner mashes convert faster, and can improve your conversion efficiency in cases where you have trouble getting complete conversion. You get maximum lauter efficiency when the volume of your first runnings are approximately the same as the volume(s) of your sparge runnings. To get equal runnings, your sparge volume should be 1/2 of your target pre-boil volume for 1X sparge, or 1/3 for 2X sparge. Your strike volume should be the sparge volume, plus your MLT dead volume, plus 0.12 gal/lb times your grain bill weight.

To determine the amount of grain needed for a recipe, you need to know your typical mash efficiency, and your desired OG. The number of gravity points you need is:

Points = Tgt Post-Boil Vol * 1000 * (Tgt OG - 1) / Mash Efficiency (in fractional form)​

The total grain weight needed is then approximately total points divided by 37 (most typical grain bills are pretty close to 37 pts/lb aggregate.)

Brew on