Sunday, 31 March 2013

Happy Easter.

For this Easter greeting, I couldn't find a suitable photograph from pictures I'd taken this year; I wanted a cheerful blue sky background! So I reverted to one I'd taken a few years ago on a photography day-course up at the London Wetlands Centre.

Thursday, 28 March 2013

Secondary Fermentation

If I have any interested friends left in 'blogland' it will be a miracle! However, in the remote chance anyone is still looking in, I'm about to bore you to tears with this the next stage in the great sap wine project. One quick check with the hydrometer shows the gravity reading has now reached 1.010. If you scroll down to my previous two posts, you can compare this against my initial reading of 1.090 (posted just a week ago). As the eventual aim is for 0.990, you can see that about 80% of the sugar has already been converted to alcohol and CO2 by the yeast. However, converting the final 20% could take several months. As the alcohol content increases, the speed at which the yeast can work gets much slower. During the vigorous Primary Fermentation, the yeast is multiplying to fill the volume of the liquid. The yeast needs plenty of oxygen at this stage, so it is often a good idea (as here) to start the wine off in a brewing bucket and stir it several time a day. But now the process is slowing I need to do the opposite and prevent the air from reaching the wine to keep out any spoilage bacteria. This stage is called the Secondary Fermentation and takes place in a demijohn with an airlock fitted in the bung at the top.
Someone once said that the art of good wine making is to spend 70% of your time sterilising everything.
Here is some of the equipment I need after I have sterilised it (including the table top).
Once everything is sterilised I can start to strain the liquid through a muslin before putting it into my demijohn.
Karen let me use her cheese strainer to leave the remaining solids (of orange, lemon and rasins) to drip and eke out as much flavour as possible :-)
Here is the result - I had to improvise with a 4 pint milk carton to take the overflow. Hopefully this will eventually yield 7 or 8 bottles.
Actually, all this wine making in the shed was cheering me up because I've been going down with a rather heavy cold. Karen also decided very sweetly, to help me to feel better by buying me this bag!

Sunday, 24 March 2013

Another Wine Update.

I am aware that all my friends in 'blogland' will have been loosing much sleep wondering what specific gravity my wine has now reached. Well let me put you all out of your misery - the reading (on the right hand side of the hydrometer) is now 1.040. Oh wow, I hear yopu all cry. Well I agree, because if you compare this with the picture below, you will see that in just a few days it has already converted half the sugar and made half the eventual alcohol content (I'm aiming for 0.900 which is the mark at the top of the right hand side). It will be several months before it has reached this.  
This evening, I have also put out my moth trap for this weeks Garden Moth Scheme survey. I'm not holding my breath though; outside, the temperature is minus one degrees and I'd be amazed if I get any moths. Oh well, even zero represents a scientific record.

Thursday, 21 March 2013

Sap Wine Update

Some people have said they are interested to see how the whole thing progresses and what happens, so here is some information about it all. Yesterday evening, I was finally able to complete the first stage of my Birch sap wine project :) . This second batch of Birch sap amounted to a gallon, so I needed to use our preserving pan to be able to boil it all with the orange and lemon zest. With citrous fruits, I always use just the zest and juice because the pith can impart an unpleasant bitter flavour. I added this to my first batch of sap into a brewing bucket - now I was ready to introduce all the other ingredients; these were: rasins, a cup of tea, a little malic and tartaric acid, some pectin enzyme,  brewing sugar and yeast nutrients.

I love the simplicity of my hydrometer - the amount it floats, depends upon how much sugar is disolved in the liquid. This is becaurse the more sugar there is in the liquid, the denser it is. Toward the top you can see 1.000 - this is the level it would float in pure water (a specific gravity of 1.000). I was aiming to get enough sugar disolved in my 'must' to reach a specific gravity of about 1.090. I have never achieved this first go - until now -yippee!!! Usually I have to fiddle about adding more sugar solution a little at a time until I get it there. As I like dry white wines, I will let this ferment right out. So with a reading of 1.090 I should obtain a wine that is nearly 12% alcohol by volume. The final reading I will aim for is 0.990, right at the very top of my hydrometer (the alcohol makes a finished wine less dense than water).

Once all the ingredients have been added, I'm ready to pitch my yeast. For wine, this is the most important part of all. Yeast is a fungus that basically converts sugar into alcohol and carbon dioxide. The more you pamper your yeast, the better the resulting wine. A good wine recipe is one that gives the yeast everything that it needs - sugar, oxygen, vitimins, some acid, nitrogenous matter, a little warmth and no competition from other yeasts and bacteria (which is why keeping everything sterile is crutial too). This picture shows the finished 'must' with the yeast sprinkled on the surface. I had to wait until the temperature had dropped to 21deg before doing this, because too warm a temperature can damage or even kill the yeast.

And here it is this evening (24 hours later). This stage, while it is fermenting in my brewing bin, is called the primary fermentation. This usually lasts about a week and during this time, the yeast is multiplying at a phenominal rate. As you can see, it has already started to froth and I need to stir it quite thoroughly, several times a day because the yeast needs plenty of oxygen while multiplying. The carbon dioxide given off helps to prevent airborne bugs from reaching the brew, but as the fermentation settles down and becomes less vigorous, I will then strain off the liquid into a demijohn and prevent the air from getting to it with an airlock. This creates is a much slower fermentation and is known as the secondary fermentation. I'll try to put this up in about a week. If anyone reading this is still awake it'll be a miracle - but if you have read this through to the end - thanks!

Saturday, 16 March 2013

Tapping Birch Trees

Welcome to my first go at tapping a Birch tree! The idea here is to obtain sap to make a rather novel white wine.
In all, I set up three of these last Thursday lunch time near the workshop. It is very important to do this in such a way so as to avoid harming the trees involved. The rules to achieve this are to take no more than a gallon from any one tree; select trees that are fairly mature; make bore holes no deeper than 1/2 inch and plug them afterwards with wooden dowels to prevent the trees from continuing to bleeding.
Hey presto! In 24 hours I had collected four pints (about half the quantity I need for my recipe) with half this amount coming from just one tree. In the UK (depending upon the weather) the sap rises in the first half of March, but it was interesting to see how quantities varied from one tree to another. Although I was delighted with this result, I had to postpone tapping because the weather was turing very windy, with heavy rain and freezing temperatures overnight. 
Birch sap is supposed to be very nutritious, full of minerals, trace elements, antioxidants and natural sugars etc. but it lacks certain essentials for a well balanced wine, especially acids and tannin. So, among other things, the recipe requires the zest and juice of two lemons and two oranges to give the correct amount of citric acid and a cup of strong black tea for the tannin. Birch sap can also go off fairly quickly, so I decided to process this first batch by boiling it for 20 minutes with the zest of one lemon and one orange. Then once it had cooled to room temperature, I put it in the freezer to preserve it for later. So watch this space to see how the whole thing progresses!! 
Earlier this week, the weather was even worse with yet more snow and sub-zero temperatures but it enticed this Fieldfare into the garden (they love apples) - no doubt wanting to feed up before flying back to North Scandinavia for the breeding season.
With a wind chill factor reported at minus 11, our daffodils were not very happy ...
but this Robin decided to pose for me - christmas card style.
Hopefully next week will give me an opportunity to get the rest of the sap I need!!