So the masochist with the short memory for pain decided I should make another batch of birch beer. The first batch I made was the best 'beer' I've ever had, commercial or Homebrew. That said, it takes A LOT of sap to make 5 gallons of beer. To give you some idea, it takes 50 gallons of maple sap to make one gallon of maple syrup. It takes 100 gallons of birch sap to make one gallon of birch syrup. Fortunately, I'm not making syrup! But... It still takes about 50 gallons of birch sap to make wort with the specific gravity to make 5 gallons of good beer. I need to boil the sap down to the point where the specific gravity is about 1.140. With  pure water being 1.000. When I checked the sap this morning with my hygrometer I couldn't get a measurement different than pure water.

I tapped 7 trees yesterday afternoon. Four with gallon jugs and three with half-gallon jugs. This morning I had the three-and-a-half gallons you see in the picture.

If history repeats itself, I should get about a gallon per tree per day. (A little less from some, a little more from others.) At that rate, it should take me about a week to get the 50 gallons I want.

I started the boil today. It will continue essentially non-stop for the full week. Hence the 'masochist' comment. If I get REALLY ambitious AND the trees don't leaf out too soon, (can't use the sap once the trees start to leaf out), I may make some syrup.

Paul

To give you some idea of "how this works": At the current rate of evaporation, I'm losing about 79 ounces (61% of a gallon) per hour of boiling. I had 855 ounces to start with, (those bottles were 4 liters, not the 1 gal I thought they were), so I'll be boiling for about 5 hours to get down to approximately 1 gallon (128 ounces), of solution from 855 ounces (6.7 gal), starting solution. That's of course not enough reduction, but I don't want to take the solution down too far at the start because there would be too little of the 'final solution'. I'll take this first 3.7 gal down to 1 gal, then add the next collection amount and boil that down to 1 gal. That will be about 7+ gallons down to 1 gal which should be close to the initial gravity I want to make the beer. That will probably  be a little high, but I'll check with the hydrometer to get it where I want it.

Paul

Not a great picture, but you can see how the color has changed.


This is about half a gallon or so. When it cools to about 60F I'll take a hydrometer reading. That figure will let me know how much total sap I'll need to collect to get 5 gallons of wort at a specific gravity of ~1.140, and how many hours of boiling I have to look forward to.

Paul

So after it cooled off, the specific gravity reading was 1.03, for a change of about 3%. I'm looking for a total change of 10 to 12% - a hydrometer reading of 1.100 to 1.120.

 

Paul

Here's what that first 3.7 gallons looks like when reduced to 78 ounces:


The second batch of sap was about 3.5 gallons. After reducing it and adding it to the 1st batch the specific gravity is 1.055:


Total boiling time; about 8 hours.
Total volume of sap boiled: 7.2 gallons.
Total volume of reduced solution; about 2/3rds of a gallon.
Back-calculating from 'reduced' specific gravity and volume, the specific gravity of the sap straight from the tree is about 1.0027. Which means that the sap straight from the tree is about 0.27% sugar.

Still looking at having to boil at least 50 gallons of sap to get the 'wort' I want. At a reduction rate of .62 gallons per hour, that's a total of 80 hours of boiling.

Paul

I'm gaining perspective here, on why in the old days, monasteries were often the sources of the best beer.


:D

Terrific amount of energy used, no wonder the price of commercial stuff.

Yup and yup.

Paul

So, for various reasons, not just the comments above, I decided to calculate/estimate the cost in natural gas for going through this exercise. As it turns out, after all the add-on and taxes and everything else the gas company can do to confuse the issue, I pay $0.01047 per cubic foot of natural gas. Starting at an initial temperature of 38 degrees F, it costs me 21 cents to convert 3.7 gallons of sap to 78 ounces (0.61 gal) of 'elixir'. That turns out to be 6.25 cents of natural gass per gallon of sap boiled away. So for getting 50 gallons down to 5 gallons - boiling off 45 gallons - it's gonna cost me ~$2.81. I can live with that. In fact, double that figure for 'fudge factor', and I can still live with that $5.62 cost. :D

Paul

PS - Carrying this out to making syrup, and assuming the 100:1 ratio of sap to syrup, that's still only $6.25/per gallon. Considering that birch syrup goes for $25 per QUART, (that would be $100/gallon), AND that there's really no "farming" necessary to get the sap - it's essentially free - $25/qt seems a little high.

Paul

I checked some of the conversion factors (joules/cubic foot of natural gas for example), and the totals were significantly reduced. Check out the corrected numbers in the previous post.

For those squinting their eyes at my numbers, (I would be), here's the math:

Mass * specific heat * Delta t = energy required to boil that mass of water

Specific heat of water (sap) - 4.186 joules
Starting temperature of sap - 3 degrees C
"Ending" temperature of sap - 100 degrees C (boiling)
Delta t = 97 degrees C
Mass of sap to boil - 12733 ml (or cubic centimeters)

 Mass  . . .  S.H.  .  .Dt = Energy
12733 * 4.186 * 97 = 5170030 joules

joules per cubic foot of natural gas - 1052631

5170030j / 1052631j/cu ft of NG = 4.9 cubic feet of natural gas
4.9 cu ft of NG / 3.36 gallons of sap = 1.46 cubit feet of NG to boil 1 gallon of sap
1.46 cu ft/gal * 0.01047 $/cu ft = 0.015 $/gal or 1.5 cents to boil one gallon of sap.

There's the math. You can check the numbers for yourselves. I had to do it three times to convince myself!

Paul

So how goes this endeavor?


Still pulling 3+ gallons per day?


That should put you at or near your goal by now eh?
No?

Actually, it was 3+ gallons twice a day when I started, but it got clear and cold overnight and started freezing pretty hard. That slowed production down to about 3+ gallons a day for two days. Right now, I've got about 2.5 gallons of 'wort' that has my target density of 1.12. (Since density is a ratio, the value is the same regardless of the units.) And that's boiling 9 to 10 hours A DAY!

I had hoped to get 5 gallons of 'wort', but... turns out that the density of the sap coming out of my trees is at the bottom of the scale for birch trees. (After all the boiling, we have a better estimate of the sugar content of the sap: About 0.5%. ) So... I am considering a few options.

1) Make up the balance with maple syrup. (Turns out, the OFFICIAL sugar content of maple syrup has to be 66% or greater.)
2) Make up the balance with honey.
3) Make up the balance with malt extract. (The "normal" stuff used to brew beer.)
4) Lower the starting specific gravity from 1.12 to 1.1.

Honey is cheaper than maple syrup, but I've already bought a quart of maple syrup. One quart of maple syrup will make 5 quarts of 1.12 density 'wort'. Therefore, if I could get 3.75 gallons of birch 'wort', I could add a quart of maple syrup and a gallon of water and have my 5.0 gallons of 1.12 density 'wort', but that would be a little disappointing. It would be 'adulterated' birch beer. I could do the same with malt extract, but again, 'adulterated'. I am inclined to reduce the starting specific gravity to 1.100. That way, it would still be 'real' birch beer.

The last/first time I did this, I didn't measure the density of the sap or the starting density of the 'wort' and I didn't take any notes. I just boiled sap 'til I got tired of doing it and the 'wort' looked 'good enough'. Based on this experience, I am pretty sure I didn't have a starting density of 1.120 with that first batch.

I will be stopping the fermentation when the ABV (Alcohol by Volume) is ~6%. Starting at 1.12 SG, and stopping at ABV ~6% means that the final gravity will be 1.06, or 6% suger. That's pretty sweet. I like sweet. However, I'm thinking that starting at 1.10 and stopping at an ABV of ~6% would mean 6% alcohol and 4% sugar. I could even go down to a SG of 1.090 and stop at 1.03 for a ~6% ABV and 3% 'sweetness'.

I didn't take any notes from the first effort because it was just sort of a lark. At the time, I didn't realize/know that anyone had ever made birch beer. I wasn't sure it would "work". (I knew it would ferment, but I had no idea what the final result would be.) Of course it turned out spectacularly. Therefore, I am not terribly concerned about starting at 1.120 density. What I want is a sweet beer that's not too "alcoholie". Something kind of like German "Malzbier", if you know what that is. That's essentially what the first batch ended up being.

To date, I've almost reached the planned 50 gallons of sap. Unfortunately, given the low sugar content from my trees, that 50 gallons isn't providing the sugar I had hoped for. Also, the weather has warmed up during the days, but we still have over-night temps in the 20s (negative centigrade). With these warm days, the birches will be leafing out pretty soon. As soon as the first leaves burst out, the "sapping" is over. The sap gets cloudy and bitter. (Those people that like 'hoppy' beer might actually like that! I HATE 'hoppy' beer.) So one way or the other, I'll be 'done' pretty soon. I'm still collecting and intend to for the next two or three days at least.

I think 'you' may be able to more appreciate why I don't make birch beer every spring.

I'll take some pictures of the 'wort'. It is impressively dark.

Paul

PS - I thought originally that my starting density would be 1.14, but that's way too high. If you wanted a high ABV of 10 or so, (and still have 4% sugars), that would be OK, but I don't want that high an alcohol content.

Paul

As promised...

Paul

I look forward to reading the reviews of the finished product.
Although I can't imagine a sweet or even sweet-ish bier.
 I'm not a big fan of the hoppy stuff like IPAs, but I do like to know there were some hops used in the making.


 I'm not a big beer/bier drinker, but I have been known to lust after the rich, malty Oktoberfest brews that Spaten makes limited amounts of every year.  It's heavy and hearty, and I liken it to having "liquid bread" with a meal.
 
One of the reasons I don't drink much beer anymore, is I've found that nearly all American beers with rice, wheat etc (and some formaldehyde thrown in) in the formula tends to bring on the middle-of-the-night leg cramps I despise.


So I stick with the German imports that adhere to the Reinheitsgebot or "purity law" that dictates 4 ingredients only when I do have a bier.
 Water, Hops, barley (malt), and now yeast.

But I still can't too drink much of it, or the cramps return.

Anywho, I'm glad to hear of your progress, so keep us posted.

I like THICK, dark, sweet, beer. More like pop than beer, really. Clearly I'm not a beer snob, BUT, I learned to drink beer drinking German beer, and while there are some genuinely disgusting German beers, American beers, (except some 'artisan' beers), just don't 'do it' for me. I either make my own or drink something else. Actually, the American beers I like are Budweiser and Pabst Blue Ribbon, two beers generally reviled and bad-mouthed by beer connoisseurs.

Too bad about the leg cramps. I get those when I eat eggplant. So I don't eat eggplant.

Paul